| circumspect(adjective, sneaky, secretive) |
| classified(adjective, obscure, secret, unknown, clandestine) |
| cloaked(adjective, sneaky, secretive) |
| conniving(adjective, mean, smooth, dishonest, cunning) |
| deceptive(adjective, mean, smooth, smart, false) |
| designing(adjective, mean, smooth, false, cunning) |
| esoteric(obscure, strange, unknown, clandestine, underground) |
| fraudulent(dishonest, cunning, deceitful, dubious, secret) |
| in ambush(expression, close, clandestine, underground, undisclosed) |
| incognito(close, secret, hidden, spy, clandestine) |
| masked(adjective, sneaky, secretive) |
| on the sly(expression, idiom, secret, private, hidden) |
| plotting(adjective, mean, smooth, cunning, knowing) |
| recondite(adjective, obscure, strange, unknown, clandestine) |
| restricted(adjective, secret, clandestine, underground, undisclosed) |
| retired(adjective, secret, sneaky, stealthy) |
| shady(adjective, dishonest, cunning, deceitful, dubious) |
| sinister |
| smooth(adjective, mean, cunning, knowing, sly) |
| stealth(noun, secret, hidden, spy, covert) |