Oh-so-precious (4)
I believe the answer is:
twee
'oh-so-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 quaint" , "Sentimental, quaint" , "Small and sweet (colloq.)" , "Precious - sentimental" , "Affectedly pretty" .)