Is Definitely An Adverb? | Usage And Placement Rules

Yes, definitely is an adverb that signals certainty and often sits before the main verb or after a form of “be.”

“Definitely” is one of those words people use all the time, then pause and think, “Wait… what part of speech is that?” It’s a fair question. The word can move around, so the pattern isn’t always obvious.

This guide clears it up in plain English. You’ll see what it modifies, where it fits, and how to avoid common placement and spelling problems.

How “Definitely” Works	Where It Often Goes	Sample Sentence
Adds certainty to an action (verb)	Before the main verb	I definitely agree.
Adds certainty to a state (linking verb)	After “be”	She is definitely ready.
Fits between an auxiliary and main verb	After the auxiliary	They have definitely finished.
Pairs with modals (can, will, should)	After the modal	You should definitely call.
Strengthens a negative	Before “not” or after the first verb	I definitely do not mean that.
Acts like a sentence adverb (whole clause)	Start, mid, or end of the clause	Definitely, we can try again.
Stands alone as a short reply	As a one-word answer	“Are you coming?” “Definitely.”
Boosts an adjective	Right before the adjective	That’s definitely true.

Is Definitely An Adverb? Clear Answer And Why

If you’ve typed is definitely an adverb? into a search bar, the clean answer is yes. “Definitely” is an adverb because it modifies meaning by adding a level of certainty. It can attach to a verb (“agree”), an adjective (“true”), or even the whole message of a clause.

Adverbs often tell us how, when, where, how often, or to what degree something happens. “Definitely” works in the “to what degree / with what certainty” lane. It tells the reader that the speaker isn’t guessing or hedging.

If you want a reference definition, Merriam-Webster’s entry for adverb describes the category “definitely” belongs to.

What “Definitely” Modifies

Think of “definitely” as a certainty marker. It doesn’t name a person, place, or thing. It doesn’t label an action as a verb does. It doesn’t rename a noun the way an adjective can. Instead, it adjusts the strength of what comes next.

Verb: I definitely remember it well.
Adjective: That plan is definitely safe.
Whole clause: Definitely, we should leave early.

What “Definitely” Is Not

It’s not a noun (“a definitely”), and it’s not an adjective on its own. When people treat it like an adjective, it usually shows up as a casual slip, like “That’s a definitely.” In standard written English, that won’t read well.

Definitely As An Adverb In Real Sentences

Knowing the label is nice, but placement is where most writers get stuck. The good news: English gives you more than one “correct” spot, as long as the sentence stays smooth and the meaning stays clear.

When It Modifies A Verb

When “definitely” strengthens an action, it often appears before the main verb. This spot is common in daily writing because it keeps the emphasis close to the action word.

I definitely need a new charger.
She definitely noticed the change.

When It Modifies An Adjective

When “definitely” strengthens an adjective, it usually sits right in front of it. This pattern is handy when you’re describing a state, a quality, or a result.

The answer is definitely correct.
This room is definitely quiet.

When It Applies To The Whole Message

Sometimes “definitely” comments on the whole idea, not one word. In that case, you may see it at the start, tucked into the middle, or placed at the end. Each choice shifts the rhythm a bit.

Start: Definitely, I’ll be there.
Middle: I’ll definitely be there.
End: I’ll be there, definitely.

Where To Put Definitely In A Sentence

Placement rules for “definitely” aren’t about one rigid location. They’re about keeping the reader from tripping. Use the patterns below as your default, then adjust when tone or rhythm calls for a different spot.

Before The Main Verb

This is the most common home for “definitely” with a simple present or simple past verb. It keeps the certainty marker close to the action.

I definitely understand your point.
They definitely left early.

After A Form Of “Be”

When the main verb is a form of “be” (am, is, are, was, were), “definitely” often lands right after it.

He is definitely honest.
We were definitely late.

Between An Auxiliary And The Main Verb

If your verb phrase uses an auxiliary (have, has, had, will, would, can, could, should, may, might, must), place “definitely” after the first auxiliary. This keeps the verb phrase intact and clean.

She has definitely seen it.
They will definitely arrive soon.

With Negative Forms

Negatives can get crowded. If you put “definitely” in the wrong spot, the sentence can sound like it’s stepping on its own feet. Two placements tend to read well.

After the first verb: I do definitely not agree. (This sounds awkward.)
Better: I definitely do not agree.
Also good: I do not definitely agree. (This can change the meaning: not fully certain.)

Notice the meaning shift in the last pair. “I definitely do not agree” is a firm no. “I do not definitely agree” leaves room for doubt.

In Questions

With questions, “definitely” often sits after the subject or after the first auxiliary. Aim for the spot that sounds like real speech when you read it out loud.

Do you definitely want to go?
Is she definitely coming?

At The End Of A Clause

Ending with “definitely” can sound casual and a bit punchy. It’s common in dialogue and friendly writing. In formal writing, it can still work, but use it with care so it doesn’t feel like a throw-in.

I’ll check the report tonight, definitely.

Commas With “Definitely”

Most of the time, “definitely” doesn’t need commas. Commas enter the picture when “definitely” works as a sentence opener or a parenthetical aside.

Comma After A Sentence-Opening “Definitely”

When “definitely” starts the sentence and comments on the whole idea, a comma can help the reader hear the pause.

Definitely, we should double-check the data.
Definitely, that wording sounds clearer.

No Comma In The Middle In Most Cases

When “definitely” sits in its usual mid-sentence spot, skip the commas.

I definitely understand the assignment.
They have definitely finished the draft.

Common Errors With Definitely

Most mistakes with “definitely” fall into two buckets: spelling and placement. Fix those, and your sentences will read clean.

The Misspelling “Definately”

The most common misspelling drops the second “i”: definately. A quick trick is to spot the root “finite” inside “definitely.” If “finite” is there, the spelling is on track.

Awkward Placement In Verb Phrases

With multi-part verbs, it’s easy to drop “definitely” in a spot that breaks the flow. If the sentence sounds clunky, move “definitely” after the first auxiliary or before the main verb.

Using It Where The Tone Doesn’t Fit

In academic or legal writing, “definitely” can sound too conversational if it’s used as a stand-alone reply or tossed at the end. In that context, “certainly” or a more precise claim backed by evidence may fit better.

Definitely Vs Certainly Vs Surely

All three words express confidence, but they land differently. Picking the right one can sharpen tone.

Cambridge Dictionary’s grammar section on adverbs is a solid place to see how adverbs operate across sentence patterns.

Definitely

“Definitely” feels direct and conversational. It’s common in daily talk, emails, and friendly writing. It can still appear in formal work, but it can sound assertive, so use it when you mean it.

Certainly

“Certainly” often sounds polite and a bit more formal. It works well in customer service writing, professional replies, and formal requests.

Surely

“Surely” can express confidence, but it can also carry a hint of expectation or mild pressure. In some contexts, it can sound like the writer is nudging the reader toward agreement.

Meaning Shifts You Can Hear

Placement can alter meaning, most often with negatives.

Firm certainty: She definitely didn’t call.
Unclear certainty: She didn’t definitely call. (She may have called, but the speaker isn’t sure.)
Different emphasis: She didn’t call, definitely. (Casual tone; the pause changes the feel.)

Table Of Common Placement Patterns

This table groups the placements you’ll see most often, along with the tone each one tends to carry. Use it as a quick scan when you’re revising.

Placement Pattern	Typical Tone	Sample
Before main verb	Neutral, clear	I definitely agree.
After “be”	Neutral, smooth	It is definitely true.
After first auxiliary	Neutral, standard	They have definitely finished.
Sentence start + comma	Emphatic	Definitely, we should leave.
Sentence end	Casual	We’ll go tomorrow, definitely.
Right before adjective	Clear emphasis	That’s definitely helpful.
Short reply	Conversational	“Yes.” “Definitely.”

Practice Moves That Make Placement Easier

If you’re unsure where to place “definitely,” try a swap test. Write the sentence, then read it with “definitely” in two spots. Keep the version that sounds natural and keeps meaning steady.

Simple verb: Put “definitely” before the verb. “I definitely agree.”
With “be”: Put it after “be.” “She is definitely ready.”
With an auxiliary: Put it after the first auxiliary. “They have definitely finished.”
With a negative: Check meaning. “I definitely do not agree” is firm. “I do not definitely agree” is less firm.
As emphasis: Start the sentence with a comma when the pause helps. “Definitely, we can try again.”

Style Notes For School And Work Writing

“Definitely” is fine in school writing when it fits the task. In formal essays, pair confidence words with evidence, or write the claim in a more specific way.

When “Definitely” Sounds Too Strong

“Definitely” can feel like a final verdict. If your statement is a hypothesis or a claim still being tested, that tone can clash with the task. Use it for statements you can back up, or keep it for personal voice in reflection writing.

When “Definitely” Helps

In emails, notes, and daily writing, “definitely” can make a sentence feel friendly and decisive. It’s often useful in planning messages, quick confirmations, and clear commitments.

Quick Self-Check Before You Submit

Use this checklist during revision.

Did you mean certainty, or did you mean emphasis?
Is “definitely” placed near the word it strengthens?
If the sentence has an auxiliary, is “definitely” after the first auxiliary?
If there’s a negative, does your placement match the meaning you want?
Did you spell it “definitely,” not “definately”?
Could you remove “definitely” without changing the core facts?

If the same paragraph uses “definitely” more than once, it can sound repetitive. Cut one and let the facts carry the line.

So yes—is definitely an adverb? It is. Once you treat it as an adverb of certainty and place it where it reads smoothly, the sentence starts to feel natural again.