Form a curve (4)
I believe the answer is:
bend
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">form a curve</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 bend that I've seen before include "Lean forward" , "Influence, bow" , "Stoop; knot" , "Crook" , "Country; bird" .)