Smile ingratiatingly (6)
I believe the answer is:
simper
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">smile ingratiatingly</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 simper that I've seen before include "Primes to laugh affectedly" , "Primes (anag.)" , "Smile self-consciously" , "Smile in an affected manner" , "Smirk" .)