A compliment is an expression of respect or admiration, like, "You're such a good writer," or "You know so many words!" Keep them coming.
Don't confuse compliment with complement. The second word means something that completes, as in, a piece of chocolate cake is the perfect complement to a meal. The two words are related, though. Both come from the Latin complere, which means "to complete" or "to fill up." The idea is that if you pay someone a compliment, you fill up your obligation to be polite. For the moment, anyway.
