Conceited and self-satisfied (4)
I believe the answer is:
smug
'conceited and self-satisfied' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for smug that I've seen before include "goody-goody" , "Irritatingly self-satisfied" , "irritating expression" , "Arrogantly complacent" , "Self-righteous" .)