Insincere flattery (5)
I believe the answer is:
smarm
'insincere flattery' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for smarm that I've seen before include "Smooth talking" , "oil" , "Obsequious flattery" , "Fawning" , "Superficially ingratiating behaviour" .)