One letter separates flattery from completion. The history of the two words — and the ‘i’ trick — makes the choice automatic.
The short answer
A compliment is praise: ‘What a compliment!’ A complement completes something or goes beautifully with it: ‘The sauce complements the dish.’ Remember that a compliment is something I say to praise you — the letter i is your signal.
This pair confuses writers for an unusually forgivable reason: compliment and complement are not just homophones, they are historical twins. Both descend from the Latin complēre, ‘to fill up’. A compliment figuratively fills a person up with good feeling; a complement literally fills something up to completeness.
Compliment: the praise word
As a noun, a compliment is an expression of admiration. As a verb, to compliment is to give one. Note complimentary, which carries a second sense: given free of charge (‘complimentary tickets’).
He complimented her on the clarity of the report.
The hotel offered a complimentary breakfast.
Complement: the completing word
A complement is whatever completes a set or pairs so well with something that both are improved. In grammar — fittingly — a complement is the word or phrase that completes a clause’s meaning (‘She is a doctor‘). In mathematics and biology the word has technical lives of its own, all built on the same idea of completing.
The sharp cheese complements the sweet chutney.
A full complement of staff was on duty.
| compliment | complement | |
|---|---|---|
| Meaning | Praise; free of charge | That which completes or pairs well |
| Adjective | complimentary (flattering; free) | complementary (mutually completing) |
| Signal letter | i — ‘I praise’ | e — ‘complete’ |
The adjective pair causes the most damage in professional writing. Colours, skills and angles are complementary; remarks and wine on the house are complimentary. A ‘complimentary angle’ would be a very polite corner.
Frequently asked questions
Which one is ‘complimentary breakfast’?
Complimentary with an i — here it means free of charge, from the same word as praise. A ‘complementary breakfast’ would be one that completed your stay in a structural sense, which is not what the hotel means.
Is there an easy way to remember?
Two, in fact: compl-I-ment contains I, the person doing the praising; compl-E-ment contains the E of ‘complete’.
