Not immediately obvious, understated
I believe the answer is:
subtle
I believe this clue is a double definition.
'not immediately obvious' is the first definition.
(I've seen this before)
'understated' is the second definition.
(I've seen this in another clue)
(Other definitions for subtle that I've seen before include "Delicately complex and understated" , "Not blatant" , "Such distinctions are hard to see" , "Able to make fine distinctions" , "Very nice" .)