Overly flattering (6)
I believe the answer is:
smarmy
'overly flattering' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for smarmy that I've seen before include "Fawning" , "Unctuous" , "Excessively flattering (R, not L)" , "Smooth" , "Obsequious" .)