Behave harshly towards (4,2)
I believe the answer is:
step on
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">behave harshly towards</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 step on that I've seen before include "crush" , "Behave harshly towards" .)