Grins (6)
I believe the answer is:
smiles
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">grins</span>' is the definition.<br/ ><span class="explanation-format__explanation">('smile' can be a synonym of 'grin')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for smiles that I've seen before include "expresses pleasure" , "Beams, grins" , "Gives visible sign of pleasure" , "Shows signs of pleasure or amusement" , "Facial expressions showing pleasure" .)