clandestine
/klænˈdɛstɪn/adjective
Carried out in secret, often because the activity is not allowed or approved of.
Example sentences
- “The two ministers held a clandestine meeting away from the press.”
- “Spies passed clandestine messages hidden inside hollow coins.”
Applies to activities, meetings, and operations rather than to people. 'Covert' is the usual military synonym.