Sticks around, complacent (4)
I believe the answer is:
smug
'complacent' is the definition.
(smug can mean complacent or self-satisfied)
'sticks around' is the wordplay.
'sticks' becomes 'gums'.
'around' says the letters should be written backwards.
'gums' back-to-front is 'SMUG'.
(Other definitions for smug that I've seen before include "Unpleasantly complacent" , "Self-satisfied, stuffy" , "Self-satisfied, complacent" , "Self-satisfied and vain" , "Spruce" .)