Self-righteous
I believe the answer is:
smug
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">self-righteous</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 smug that I've seen before include "Self-satisfied, complacent" , "Unpleasantly complacent" , "Arrogantly complacent" , "Smirking" , "goody-goody" .)