| exclusive(adjective, special, intimate, personal, confidential) |
| feline(false, artful, deceptive, sneak, skulking) |
| foxy(adjective, false, secret, sly, artful) |
| incognito(secret, hidden, spy, underground, undisclosed) |
| intimate(special, personal, confidential, hush-hush) |
| mysterious(adjective, quiet, secret, unknown, hidden) |
| obscure(adjective, secret, unknown, hidden, underground) |
| on the QT(expression, adjective, idiom, adverb, dishonest) |
| on the quiet(expression, adjective, idiom, adverb, dishonest) |
| personal(adjective, special, intimate, confidential, hush-hush) |
| recondite(adjective, secret, unknown, hidden, underground) |
| reserved(adjective, secret, sneaky, stealthy) |
| retired(adjective, secret, sneaky, stealthy) |
| secluded(adjective, secret, unknown, hidden, personal) |
| secretly(adverb, slyly, underhandedly, surreptitiously) |
| shifty(dishonest, cunning, deceitful, sneaky, underhanded) |
| slinking(secret, private, hidden, sneak, sneaky) |
| slinky(sneak, skulking) |
| sneak(underground, undisclosed, skulking) |
| sub rosa(expression, adjective, idiom, adverb, show) |