Insignificant worker (3)
I believe the answer is:
cog
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">insignificant worker</span>' is the definition.<br/ ><span class="explanation-format__explanation">(a cog in a machine)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for cog that I've seen before include "one engaged in revolutionary activity" , "Minor person in organisation" , "Each of series of teeth on wheel" , "Junior official" , "Tooth on gearwheel" .)