Not in a position (to do) (6)
I believe the answer is:
unable
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not in a position to do</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 unable that I've seen before include "Lacking the necessary skills" , "Old, weak" , "Not strong enough" , "Incompetent or powerless" , "Not in a position (to)" .)