What Is an Interjection? Definition, Types, and Examples

Definition: What Is an Interjection?

An interjection is a word or phrase that expresses a sudden feeling or reaction. Unlike most parts of speech, interjections have no grammatical connection to the rest of the sentence. They do not modify nouns like articles do, they do not describe actions like adverbs do, and they do not join clauses like conjunctions do. They simply inject emotion or reaction into speech or writing.

The word interjection comes from the Latin interiectio, meaning "something thrown in between." That is precisely what they do: they get thrown into a sentence or stand alone, expressing a feeling that the surrounding grammar does not handle.

Examples:

• Wow, that was a long meeting.
• Oh! I forgot my keys.
• Hmm, I am not sure about that.
• Ouch. That hurt.
• Hey, wait for me.

Interjections as a Part of Speech

Traditional grammar identifies eight parts of speech: noun, verb, pronoun, adjective, adverb, preposition, conjunction, and interjection. Interjections are the most grammatically isolated of the eight. A sentence can be grammatically complete with or without them, and removing an interjection never changes the core meaning of the accompanying sentence.

Compare: Oh, I forgot my keys. and I forgot my keys. The second sentence is complete and carries the same factual content. The interjection Oh adds emotional coloring but is not grammatically necessary.

Types of Interjections

Interjections can be grouped by what they express. These categories overlap, and the same word can serve different functions depending on context and tone.

Joy and Enthusiasm

These interjections express positive emotion, excitement, or celebration:

• Yay! We got the contract.
• Hooray, the results came back negative.
• Wow, this view is incredible.
• Whoo! That was a great game.
• Yes! I passed the exam.

Surprise or Shock

These mark an unexpected event or piece of information:

• Oh! I did not expect you here.
• Whoa, slow down.
• Gosh, I had no idea.
• Well, that is unexpected.
• Blimey, that is a lot of work. (British English)

Pain or Discomfort

These are often involuntary vocal responses:

• Ow! That is hot.
• Ouch, I bit my tongue.
• Argh, I spilled coffee on my notes.
• Ugh, this traffic is awful.

Hesitation or Thought

These interjections fill a pause while the speaker considers what to say:

• Um, I think the meeting is at three.
• Uh, let me check my notes.
• Hmm, that is an interesting point.
• Well, it depends on the situation.
• Er, I am not certain about that. (British English)

In written dialogue, these filler interjections add realism. In formal writing, they signal uncertainty and are usually avoided.

Attention and Greeting

These call attention or acknowledge another person:

• Hey, can I ask you something?
• Hi, nice to meet you.
• Hello! Come on in.
• Psst, over here.
• Yo, check this out. (informal)

Dismissal or Contempt

These express rejection, disbelief, or scorn:

• Bah, I have heard that before.
• Pfft, that plan will never work.
• Pshaw, he always says that.
• Whatever, it does not matter now.

Agreement and Approval

These signal that the speaker accepts or supports what was said:

• Right, that makes sense.
• Indeed, that is exactly what happened.
• Sure, I can do that.
• Okay, let me know when you are ready.
• Absolutely, we are on the same page.

Disgust or Distaste

These register aversion to something seen, smelled, tasted, or heard:

• Ew, what is that smell?
• Yuck, I am not eating that.
• Gross, someone left dishes in the sink again.
• Blech, this coffee is cold.

Primary vs. Secondary Interjections

Grammarians sometimes distinguish between two categories:

Primary interjections function only as interjections. They do not belong to any other part of speech. Examples: ouch, wow, psst, shh, ahem, phew, yikes. These words have no other grammatical role in English.

Secondary interjections are words borrowed from other parts of speech and used as interjections. They retain their original form but take on an exclamatory function:

• Shoot, I missed the deadline. (originally a verb)
• Brilliant! That solves the problem. (originally an adjective)
• Nuts, I forgot to save. (originally a noun)
• Goodness, that is a surprise. (originally a noun)
• Man, it is cold today. (originally a noun)

Phrases can also function as interjections: Oh well, Good grief, For crying out loud, Oh no, No way.

How to Punctuate Interjections

Punctuation signals the emotional strength of an interjection. There are three main options, and the choice affects how the reader perceives the intensity.

Exclamation Mark: Strong Emotion

Use an exclamation mark when the emotion is sharp, sudden, or intense. The interjection becomes its own sentence:

• Wow! That is impressive.
• No! Stop the car.
• Help! Someone call an ambulance.

The sentence that follows begins with a capital letter because the exclamation mark ends the interjection as a complete unit.

Comma: Mild or Moderate Emotion

Use a comma when the interjection is part of a flowing sentence and the emotion is moderate. The sentence continues after the comma:

• Oh, I see what you mean.
• Well, that is one way to look at it.
• Hey, do you have a minute?

The word after the comma is lowercase (unless it is a proper noun).

Period: Understated or Dry Emotion

A period after a single-word interjection creates a flat, dry, or darkly comic effect. It is a deliberate stylistic choice, more common in fiction and informal writing:

• Great. Another Monday.
• Oh. So that is how it is.
• Fine. Do it your way.

Interjections Within a Sentence

When an interjection appears mid-sentence, it is set off with commas on both sides:

• The proposal, unfortunately, was rejected.
• He was, ahem, not entirely honest in his report.

Note that unfortunately and ahem here are functioning as interjective elements within the sentence, not as standalone exclamations.

Interjections in Formal vs. Informal Writing

Interjections are most at home in conversation, dialogue, creative writing, and informal communication. In formal academic or professional writing, they appear rarely, if at all.

In a research paper, writing Wow, the results were significant would undermine the tone. The emotion belongs in measured, evidence-based language, not an exclamation.

In fiction, the same interjection communicates character. A character who says Hmm before every response feels contemplative. One who says Pfft comes across as dismissive. Writers use interjections intentionally to shape how readers hear a character's voice.

Common Interjections in English

Interjections and Voice in Writing

The choice of interjection can reveal as much about a character or narrator as any description. In business writing, a carefully placed Indeed or Certainly carries a very different tone than Sure or Yep. In academic writing, the absence of interjections is itself a signal: the prose is measured and impersonal by convention.

When editing dialogue or informal prose, the interjections you choose should match the character's background, age, regional dialect, and emotional state. Authentic interjection use makes dialogue sound natural; generic interjections make it feel written.

Frequently Asked Questions

Can an interjection be more than one word?

Yes. Multi-word phrases can function as interjections: Oh well, For goodness' sake, Good grief, Oh my, No way, What the heck. These phrases behave like single interjections grammatically because the whole phrase expresses one emotional reaction.

Is "yes" or "no" an interjection?

Yes and no can function as interjections when they stand alone as responses: Yes! We did it. or No, that is not right. In these cases they are not part of the grammatical structure of the following sentence. However, yes and no can also function as adverbs when they modify verbs or sentences: He said yes to the proposal.

Do interjections have to appear at the beginning of a sentence?

No. While they most often appear at the start, interjections can appear mid-sentence or at the end: That is, well, a complicated situation. or You finished already? Wow. Mid-sentence interjections are set off by commas.

Are interjections used in formal writing?

Rarely. In academic essays, business reports, or journalism, interjections are out of place in running prose. They appear in formal writing mainly within direct quotations. In business email, mild interjections in greetings (Hi, I wanted to follow up) are acceptable, but exclamatory interjections in the body of a message can come across as unprofessional.

What is the difference between an interjection and an expletive?

In grammar, an expletive is a word that fills a syntactic position without contributing meaning, such as there in There are three options or it in It is raining. This is distinct from the everyday use of the word to mean a profanity. Some profanities function as interjections when they express strong emotion, but the grammatical term expletive refers to a completely different concept.

How do I know when to use an exclamation mark vs. a comma after an interjection?

Match the punctuation to the intensity. If the emotion is sharp and the interjection stands on its own as a full response, use an exclamation mark: Ouch! That is hot. If the interjection flows into a sentence and the emotion is mild or moderate, use a comma: Oh, I see. The exclamation mark treats the interjection as a complete sentence; the comma treats it as an opener that leads into the main sentence.