Strike-breaker (4)
I believe the answer is:
scab
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">strike-breaker</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 scab that I've seen before include "Derogatory term for a strike-breaker" , "Strike breaker" , "Dried surface of wound" , "Crust that forms on a healing skin wound" , "one works during strike" .)