Clandestine \Clan*des"tine\, a. [L. clandestinus, fr. clam secretly; akin to celare, E. conceal: cf. F. clandestin.] Conducted with secrecy; withdrawn from public notice, usually for an evil purpose; kept secret; hidden; private; underhand; as, a clandestine marriage. --Locke. Syn: Hidden; secret; private; concealed; underhand; sly; stealthy; surreptitious; furtive; fraudulent. -- {Clan*des"tine*ly}, adv. -- {Clan*des"tine*ness}, n.