Use a pen (5)
I believe the answer is:
write
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">use a pen</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 write that I've seen before include "what an author must do" , "Put down in black and white" , "Compose (a text)" , "Put pen to paper" , "Draft" .)