Sadly pensive (7)
I believe the answer is:
wistful
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sadly pensive</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for wistful that I've seen before include "Regretfully longing" , "Melancholy" , "Disconsolate" , "(Of a smile) showing vague or regretful longing" , "Sadly pensive" .)