Putrefaction (5)
I believe the answer is:
decay
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">putrefaction</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 decay that I've seen before include "Putrefaction" , "Decline, decompose" , "Briefly fashionable" , "Putrefy" , "Rot, moulder" .)