(A person's) contribution (5)
I believe the answer is:
input
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">a person's contribution</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 input that I've seen before include "Contribution; enter (data)" , "Signal entering a circuit" , "Data entered to computer" , "data-feed" , "Comment, contribution" .)