Worry constantly (3)
I believe the answer is:
nag
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">worry constantly</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for nag that I've seen before include "trouble constantly" , "Pester; old horse" , "Badger with constant complaints" , "Complain, worry" , "Complain to or badger incessantly" .)