What Part Of Speech Is Against? | Word Class And Uses

If you have paused mid-sentence and asked, “what part of speech is against?”, you are not alone. The word appears in many everyday phrases, yet its role in a sentence can feel slippery. Learners often see different explanations in dictionaries and grammar books and want a clear, practical answer.

What Part Of Speech Is Against? Basic Answer

In current English teaching and in major learner dictionaries, against is almost always treated as a preposition. That means it stands before a noun, pronoun, or -ing form and links that word or phrase to the rest of the sentence. In short, against introduces a prepositional phrase.

Grammar references describe prepositions as words that show relations such as place, time, or abstract links between ideas. Common examples are in, on, at, from, and to. Against sits in the same family, but it tends to express opposition, physical contact, or protection.

Part Of Speech For Against In Modern English

If you open a reliable learner dictionary, you will see against labelled as a preposition with several closely related meanings. The detailed entry in the Cambridge grammar entry on “against” lists uses like “opposing or disagreeing with someone or something”, “touching something”, and “protecting against something bad”.

Those patterns match typical definitions of a preposition in standard grammar descriptions. A preposition links a noun phrase to another word and helps show place, time, cause, or another relation between them. Against fits that pattern in almost every natural sentence that learners need to write or read.

To see the range of uses at a glance, the table below gathers common meanings of against, classifying each as a prepositional use and giving a model sentence.

Use Type	Prepositional Function	Example Sentence
Opposition Or Disagreement	Shows that someone opposes an idea, plan, or action.	Many students were against the rule change.
Competition	Shows that one person or team is competing with another.	Our team plays against theirs on Friday.
Physical Contact	Shows that one thing touches or presses on another.	She rested her head against the window.
Protection	Shows that something gives protection from harm.	This vaccine protects against several diseases.
Background Or Contrast	Shows contrast between a subject and what is behind it.	The dark trees stood out against the snow.
Odds Or Probability	Shows chances that are not in someone’s favour.	The odds were against them at the start.
Rules Or Law	Shows that something breaks a rule or law.	Using phones in the exam room is against the rules.

Each row in the table shows against used before a noun phrase. In every case the word works as a preposition: it links the object of the preposition (the rule, the wall, the snow) to the verb or clause around it.

Main Uses Of Against As A Preposition

Most confusion about what part of speech against belongs to disappears once you look at how it behaves in real sentences. The sections below group common prepositional uses of against, show patterns, and give model lines that you can adapt in your own writing.

Against Showing Opposition Or Disagreement

One of the most frequent meanings of against is simple opposition. It links a person or group with an idea, plan, or action that they do not accept.

Common patterns include:

• against + noun phrase: “They are against late exams.”
• against + -ing form: “Many students are against starting so early.”
• be against something: “The committee is strongly against the proposal.”

In all these lines, against introduces the thing that someone opposes. The structure works the same way in political, academic, and everyday speech.

Against Showing Physical Contact Or Pressure

Another core use involves contact. Here against links an object with the surface it touches or presses on.

Typical patterns are:

• against + surface: “He leaned against the wall.”
• press against + surface: “The crowd pressed against the door.”
• rest against + surface: “She placed the ladder against the tree.”

This meaning appears in many descriptions of movement, posture, and location. Again, against comes before the noun phrase and marks the relation between that phrase and the verb.

Against Showing Protection

In health, science, and risk management language, against often marks protection from some harm. Many verbs that relate to safety use this pattern.

Typical verbs include protect, guard, insure, and vaccinate. Each can link to its object with against plus a noun phrase naming the danger.

• “This software guards against data loss.”
• “The insurance policy covers you against damage.”
• “Doctors recommend vaccines against common infections.”

The Cambridge Grammar page on against gives many similar patterns that show this protective use across academic and everyday English.

Against Showing Background Or Contrast

Writers often use against to describe contrast between a subject and a background. The word helps paint a visual picture, linking the main thing you want the reader to see with whatever sits behind it.

Common patterns include:

• “The white text stands out against the dark screen.”
• “Bright stars shone against the night sky.”
• “The building looks small against the mountains.”

In each sentence, against links a noun phrase (the screen, the sky, the mountains) to the clause and signals contrast between foreground and background.

Against Showing Rules, Law, And Odds

Finally, against can mark conflict with rules or with probability. Learners meet this use in formal notices, exam instructions, and news writing.

Typical expressions are:

• “It is against the law to falsify data.”
• “Cheating in exams is against school policy.”
• “The odds were against the team, but they won.”

Again, against works as a preposition: it brings in the noun phrase that names the law, policy, or odds that stand in conflict with the subject.

Is Against Ever An Adverb Or Adjective?

Older grammar books sometimes give mixed labels for words like against. You may see it listed as a preposition in one place and as an adverb in another. That can make a learner ask the same question again: what part of speech is against?

Take the line “The policy goes against everything we value.” Some writers might say that against works almost like an adverb here because the object is a broad idea instead of a concrete noun. Modern reference works still treat it as a preposition that introduces the phrase against everything we value.

In other lines the object stays unstated but clearly understood:

• “The team has always fought against.” (against their opponents)
• “She feels the rules are unfair but will not rebel against.” (against them)

Many linguists describe this as ellipsis. The object disappears because the reader can easily supply it from context. Even here, against keeps its usual prepositional role.

Only in unusual, older expressions might you see against described as an adjective. In everyday modern English, that label does not help learners and would confuse most readers, so teaching materials treat against as a preposition.

Using Against Correctly In Sentences

Once you know that against is a preposition, the next step is to master the structures that grow around it. The patterns below help you write natural sentences and avoid awkward word order.

Against With Nouns And Pronouns

The most common pattern is against + noun phrase. This noun phrase can be a single word, a pronoun, or a longer group of words with adjectives and modifiers.

• Against + noun: “The protest was against inequality.”
• Against + pronoun: “Many voters were against it.”
• Against + noun phrase: “The decision goes against long-standing practice.”

Notice that against always stands before the noun phrase. Placing the noun first and adding against later usually sounds unnatural in English.

Against With -Ing Forms

Against can also link to a verb in the -ing form. In that case the -ing form behaves like a noun and works as the object of the preposition.

• “She argued against raising the fees again.”
• “We voted against changing the timetable.”
• “The committee stood against delaying the project.”

This pattern appears often in academic writing, policy debates, and formal meetings. It lets you attach a whole action to against instead of a single noun.

Against In Fixed Expressions

Some expressions with against behave almost like idioms. Learners can treat them as ready-made pieces of language that still rest on the preposition pattern.

• “Against the clock” for working with limited time.
• “Against all odds” for success when success seemed unlikely.
• “Against someone’s wishes” for actions that ignore a person’s clearly stated choice.

Each phrase begins with against and a noun phrase, and each acts as a prepositional phrase in the sentence. Though the meaning may not be obvious word by word, the part of speech remains the same.

Common Learner Mistakes With Against

Because against is short and often stressed in speech, it can be easy to confuse with other small words or to place it in a strange position in the sentence. The table below lists frequent learner errors and shows smoother alternatives.

Situation	Common Mistake	Better Sentence
Missing Object	“The team fought against.” (no object)	“The team fought against their rivals.”
Wrong Preposition	“They are opposite the new rule.”	“They are against the new rule.”
Wrong Word Order	“The wall he leaned was against.”	“He leaned against the wall.”
Extra Preposition	“They protested against to the plan.”	“They protested against the plan.”
Confusing Object	“People voted against of it.”	“People voted against it.”
Formal Writing	“The law is not with their side.”	“The law is against their side.”
Double Negative Idea	“I am not against no rule.”	“I am not against any rule.”

Reading such pairs out loud helps you feel where against fits naturally in a clause. It also trains your ear to hear when the word repeats without need or lacks a clear object.

Linking Against To Wider Preposition Rules

Against belongs to the large family of English prepositions, and it behaves in the same basic way as more familiar items like in, at, on, from, and to. That means general advice on prepositions almost always applies to against as well.

The Cambridge guidance on prepositions explains that English prepositions usually form tight links with the noun phrase that follows them and that they cannot stand alone without that phrase. That general rule matches the uses of against that you saw above and can guide your own writing.

Quick Practice Ideas For Using Against

Practice makes progress. After a few rounds of such practice, you will start to notice how often English speakers and writers rely on this short word. More than anything, you will know exactly where to place it and why modern grammar treats against as a preposition almost every time it appears. That steady habit builds strong grammar instincts over time.

Here are a few simple ways to practise:

• Write five sentences where against shows opposition to an idea, then check that each one has a clear object after the preposition.
• Write five sentences where against shows physical contact, making sure it stands just before the noun phrase that names the surface.
• Collect three news headlines or academic sentences that use against, and underline the prepositional phrase in each case.