Overly precious (4)
I believe the answer is:
twee
'overly precious' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for twee that I've seen before include "Excessively sentimental" , "Affectedly dainty or quaint" , "Affectedly sweet" , "Pretty-pretty" , "Overly cute" .)