Assist illegally (4)
I believe the answer is:
abet
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">assist illegally</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for abet that I've seen before include "Incite or encourage" , "Aid and help, perhaps in crime" , "Aid as in committing crime" , "Crookedly endorse" , "Assist wrongly!" .)