| guileful(mean, smooth, corrupt, dishonest, deceitful) |
| hostile(adjective, cool, cold, sensitive, shy) |
| hugger-mugger |
| hushed(adjective, close, quiet, soft, low) |
| hushful(adjective, close, quiet, soft, low) |
| impenetrable |
| in ambush(expression, restricted, clandestine, underground, discreet) |
| in chambers(expression, adjective, mysterious, private, reticent) |
| in privacy(expression, adjective, mysterious, private, reticent) |
| in the background(expression, adjective, idiom, mysterious, private) |
| in the dark(expression, adjective, idiom, mysterious, private) |
| inaccessible(adjective, cool, cold, sensitive, humble) |
| inaudible(adjective, close, quiet, soft, low) |
| incognito(restricted, clandestine, underground, discreet, undisclosed) |
| incomprehensible |
| inconspicuous(adjective, quiet, plain, hidden, imperceptible) |
| indirect(dishonest, cunning, deceitful, sly, devious) |
| indistinct(quiet, plain, imperceptible, discreet, inconspicuous) |
| inexplicable |
| inhospitable(adjective, cool, cold, sensitive, shy) |