Cloying sentimentality (7)
I believe the answer is:
treacle
'cloying sentimentality' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for treacle that I've seen before include "Sweet, black viscous substance" , "Golden syrup" , "Viscous liquid" , "Electra (anag)" , "flattery" .)