Become narrower (5)
I believe the answer is:
taper
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">become narrower</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 taper that I've seen before include "Narrow to a point" , "One might record" , "Convex shape that narrows toward a point" , "He records" , "recording artist" .)