Not practical (11)
I believe the answer is:
theoretical
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not practical</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 theoretical that I've seen before include "Academic" , "Not linked to practice" , "concerned with supposition" , "Cheat toiler (anag) - speculative" , "Not practical; speculative" .)