Unsuspected means not guessed at by anybody. An unsuspected talent, unsuspected damage, went unsuspected for years.
It is used of good and bad alike, since an unsuspected talent and unsuspected rot are equally natural. It is a different word from unsuspecting, which describes the person rather than the thing.
1adjectiveunsuspectedNot guessed at by anybody.
“The tests revealed an unsuspected heart problem that needed urgent treatment.”
unsuspected is a quality.
From un- + suspected.
Etymology from Wiktionary, CC BY-SA