Be anxious (4)
I believe the answer is:
fret
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">be anxious</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for fret that I've seen before include "Guitar ridge; be anxious" , "Be always anxious" , "Worry excessively" , "Fog" , "Be anxious; ornament" .)