Not easy to see or understand (7)
I believe the answer is:
unclear
'not easy to see or understand' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for unclear that I've seen before include "Not definite" , "Imprecise, hazy" , "Not easy to see or understand" , "Not certain" , "Not transparent or free from doubt" .)