French existentialist philosopher (6)
I believe the answer is:
sartre
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">french existentialist philosopher</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 sartre that I've seen before include "French philosopher, 1905-80" , "Jean-Paul -, French philosopher/author" , "Jean Paul . . ., French existentialist writer" , "Sooner" , "French philosophic writer" .)