Size of paper (8)
I believe the answer is:
foolscap
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">size of paper</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 foolscap that I've seen before include "About 330 x 200 (or 400) mm size of paper" , "One would not be wise to put this on" , "Paper or book size (from its watermark)" , "Cop's foal (anag)" , "something near A4" .)