Tear up (4)
I believe the answer is:
rend
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tear up</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 rend that I've seen before include "Tear, sunder" , "split" , "Cleave" , "Tear savagely" , "Tear apart, wrench" .)