Complaint is the noun — the thing you have or make (“I have a complaint”). Complain is the verb — the action you do (“I complain about the noise”). They come from the same root, which is exactly why people mix them up, but they never fill the same grammatical slot in a sentence.
The Short Answer
If you can put “a” or “the” in front of it, or make it plural, you want complaint: a complaint, the complaint, several complaints. If it’s something a person does — an action attached to a subject like “I,” “she,” or “they” — you want complain: I complain, she complains, they complained.
- Complaint = noun. Example: “She filed a complaint with HR.”
- Complain = verb. Example: “She complained to HR.”
Why People Get It Wrong
Both words share the same Latin root, complangere, meaning to lament or beat the breast in grief. English kept both the noun and verb forms, and because they sound so close, writers sometimes reach for the wrong one under pressure — typing “I have a complain” or “please don’t complaint” without stopping to check which job the word is doing in the sentence.
The mistake usually shows up in two spots: right after an article (“a,” “the,” “my,” “this”) where a noun belongs, or right after a subject pronoun where a verb belongs. Spotting which slot you’re filling clears up the confusion instantly.
Quick Test
Ask yourself: is this word the subject or object of the sentence (noun), or is it describing what someone does (verb)? “The complaint was ignored” — noun, subject. “They complain every week” — verb, action.
Examples in a Sentence
| Word | Part of Speech | Example |
|---|---|---|
| Complaint | Noun | The restaurant received a formal complaint about the slow service. |
| Complaint | Noun | His main complaint is that the app keeps crashing. |
| Complain | Verb | Customers often complain when shipping takes too long. |
| Complain | Verb | I don’t want to complain, but this coffee is cold. |
Which to Use When
Use complaint when you’re naming a thing: a document, a grievance, an issue someone raises. It pairs naturally with verbs like “file,” “lodge,” “make,” “have,” or “receive” — you file a complaint, you lodge a complaint.
Use complain when you’re describing the act of voicing dissatisfaction. It pairs with a subject doing something: I complain, he complains, they were complaining. It also shows up as “complained” (past tense) and “complaining” (the -ing form).
One more wrinkle worth knowing: “complaint” can also work as an adjective in a narrow, older sense meaning obedient or compliant, as in “complaint to his wishes.” That usage is rare today and mostly appears in legal or archaic writing, so for everyday purposes, treat complaint strictly as the noun.
Key Takeaways
- Complaint is a noun — the thing itself, as in “a formal complaint.”
- Complain is a verb — the action, as in “they complain daily.”
- Check what comes before the word: an article (“a,” “the”) signals you need complaint.
- Check what comes before the word: a subject pronoun (“I,” “she,” “they”) signals you need complain.
- Common verb forms include complain, complains, complained, and complaining.
Frequently Asked Questions
Is it “I have a complaint” or “I have a complain”?
It’s “I have a complaint.” Complaint is the noun form, and after “a” you always need a noun, never a verb.
Is it “please don’t complain” or “please don’t complaint”?
It’s “please don’t complain.” After “don’t,” you need the base verb form, so complain is correct.
What is the verb form of complaint?
The verb form is complain (with complains, complained, and complaining as its conjugations).
Can complaint ever be used as a verb?
No, not in modern standard English. Complaint functions only as a noun today, though an archaic adjective sense meaning “compliant” exists in older texts.
What’s an example that uses both words correctly?
“After customers began to complain about the delay, the manager asked each one to submit a written complaint.”
Once you lock in that complaint names the thing and complain names the action, the mix-up tends to disappear for good. If similar noun-versus-verb pairs trip you up, browse more comparisons like this one on the site.
