Overly pretty (4)
I believe the answer is:
twee
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">overly pretty</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for twee that I've seen before include "Niminy-piminy" , "Rather too pretty" , "Affectedly dainty or quaint" , "Pretty-pretty" , "Sentimentally sweet" .)