Pleased with oneself (4)
I believe the answer is:
smug
'pleased with oneself' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for smug that I've seen before include "Showing excessive self-pride" , "Self-satisfied and vain" , "Full of oneself" , "Prim" , "Smirking" .)