(1):

(n.) An expression, by word or act, of approbation, regard, confidence, civility, or admiration; a flattering speech or attention; a ceremonious greeting; as, to send one's compliments to a friend.

(2):

(v. t.) To praise, flatter, or gratify, by expressions of approbation, respect, or congratulation; to make or pay a compliment to.

(3):

(v. i.) To pass compliments; to use conventional expressions of respect.