| fair-weather(fickle, untrustworthy, unprincipled) |
| faithless(fickle, untrustworthy, unprincipled, dirty-dealing) |
| falsehearted(fickle, untrustworthy, unprincipled, recreant, dirty-dealing) |
| fickle(untrustworthy, unprincipled, dirty-dealing) |
| fly by night(expression, idiom, fickle, untrustworthy, unprincipled) |
| for eyes only(expression, idiom, sensitive, private, confidential) |
| for no other ears(expression, idiom, adverb, sensitive, confidential) |
| foresworn(fickle, untrustworthy, unprincipled, dirty-dealing) |
| groundward |
| guarded(reserved, mysterious, private, reticent, taciturn) |
| guileful(dishonest, cunning, deceitful, sneaky, underhanded) |
| hermetical(unknowing, unbriefed) |
| hidden away(expression, sensitive, sub-rosa) |
| hot-headed(unknowing, hermetical, unbriefed) |
| huggermugger(adverb, secretly) |
| ignorant(unknowing, hermetical, unbriefed) |
| imperceivable(unknowing, hermetical, unbriefed) |
| in a corner(expression, idiom, unknowing, hermetical, unbriefed) |
| in ambush(expression, sensitive, clandestine, underground, undisclosed) |
| in disguise(expression, furtively, incognito) |