Kept or done secret or in secret, especially because illicit or of questionable nature.
Late 16th century: from french clandestin, from latin clandestīnus, from clam 'secretly' + destinare 'destine'.
- The couple were caught in a clandestine affair.
- He took a clandestine approach to his business dealings.
- The secret group conducted their meetings in a clandestine manner.
- The police found evidence of a clandestine drug operation.
- She had a clandestine meeting with her lover.