Compliment vs Complement

I had an email at work recently which read “This new software will compliment the existing system.” Can you spot what’s wrong with that sentence?

If you get confused by the difference between compliment and complement, or if you’re unsure which to use when, read on.

Compliment

Merriam-Webster defines a compliment as “an expression of esteem, respect, affection, or admiration; especially : an admiring remark”. It comes from Middle French, via the Italian complimento, and the Spanish cumplimiento, which originates from the Latin verb cumplir: to be courteous.

For example:

I was trying to pay that girl a compliment, but she ignored me.
Sometimes he blushes when you offer him a compliment.

In the plural, compliments can also mean best wishes. It is often used as “with compliments” such as on a compliments slip (a small piece of letter-headed paper, often used by companies for a quick note to a customer or client when a full sheet would be too large.) You also see the phrase “with compliments of the season” in greetings cards.

The verb “to compliment” is very similar, meaning “to pay a compliment to”. Note that it is a transitive verb so must have an object. For example:

Are you trying to compliment me, or trying to insult me?
When he complimented the girl on her dress, his friends laughed at him.

Complimentary

The adjective complimentary is closely related to the word compliment, and in this context it can mean either “expressing or containing a compliment” or “favourable” (Merriam-Webster):

My mother made some very complimentary remarks about my choice of shoes.
The new restaurant has a very complimentary write-up in the local newspaper.

Complimentary also has the meaning “free”, when something is given as a courtesy or favour:

Please accept these complimentary tickets.
I thought that the mini-bar was complimentary, but we were charged for our drinks.

Complement

The word complement comes from the same root as complete. It has nothing to do with being courteous, and comes directly from Middle English, from the Latin word complementum. Merriam-Webster’s first definition is “something that fills up, completes, or makes perfect”, and it can also be used to mean “the quantity, number, or assortment required to make a thing complete”, though can sound a little odd or old-fashioned in this context:

We had the full complement of pots and pans.
Our store does not have enough employees to work the required complement of hours.

Complement is often used in scientific, technical or academic areas of discourse, where the complement of X supplies what X is missing, thus making a complete whole. Examples of this usage are:

Complement good (economics)
Complementary colour (art)

You can find a fuller list in Wikipedia’s entry for the term Complement.

In everyday writing, complement is more often used as a verb. Again, it is a transitive verb:

The illustrations complement the text.
Our new software will complement the existing product.

So, my email correspondent should have written that “This new software will complement the existing system.” But I suspect she wouldn’t have replied to compliment me if I’d written back to point out the mistake…

Ali on August 8, 2008 Subscribe to our RSS Feed

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5 Responses to “Compliment vs Complement”

Tarah on August 8th, 2008 4:55 pm

Hi

It should be ‘everyday writing’; not ‘every day writing’. And colons should always follow complete sentences, not fragments.

But thank you for this article. I see people mistake ‘complement’ for ‘compliment’ far too often.
Ali on August 9th, 2008 3:48 pm

Hi Tarah,

Well spotted on the “every day writing” — I’ve changed it to “everyday” now!

I’m not so sure on the colon issue — I agree some guides do say colons should always follow an independent clause (ie. one that could stand alone as a sentence). However, there are numerous examples of colons NOT being used in this manner, eg. “Dear Sir:” at the start of a letter.

If I find out a definitive answer, I’ll amend the colons, though!
Tarah on August 10th, 2008 7:49 pm

Great stuff, Ali!
kumar p. m on September 2nd, 2008 12:56 pm

i liked your article.and corrected my mistake.thanks.
GBotGirl on November 11th, 2008 3:47 pm

Tarah,
From my understanding, a sentence should not start with a ‘But’.