| covert(adjective, show, secret, private, restricted) |
| furtive(adjective, secret, sneaky, secretive) |
| surreptitious(adjective, dishonest, deceitful, secret, hidden) |
| hidden(verb, adjective, secret, underground) |
| undercover(adjective, adverb, show, dishonest, secret) |
| concealed(adjective, obscure, secret, unknown, hidden) |
| private(adjective, intimate, secret, unknown, hidden) |
| stealthy(adjective, quiet, dishonest, secret, hidden) |
| underhand(adjective, deceitful, secret, sneaky) |
| hush-hush(adjective, adverb, show, informal, dishonest) |
| underground(adjective, secret, unknown, hidden) |
| sneaky(adjective, quiet, dishonest, deceitful, secret) |
| cloak-and-dagger(adjective, show, full, secret) |
| illicit(adjective, secret, legal, forbidden) |
| under wraps(expression, adjective, idiom, adverb, show) |
| artful(adjective, false, secret, deceptive) |
| closet(noun, adjective, special, intimate, secret) |
| fraudulent(adjective, dishonest, cunning, deceitful, secret) |
| foxy(adjective, false, secret, artful) |
| on the quiet(expression, adjective, idiom, adverb, dishonest) |