Wiktionary
nonobvious
a. Not obvious.
Usage examples of "nonobvious".
He smiled at us around his Popeye pipe, reached into a nonobvious fold of his sarong, and produced a key.
Looking at everything was a sure sign that he didn't know what the hell he was doing yet, but it was the only way he'd ever found to smoke out the nonobvious clue that everyone else had overlooked.
A subsurface view, and only using a narrow range of frequencies, reveals a nonobvious large-scale structure.