Razor sharpener . . . (5)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">razor sharpener</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 strop that I've seen before include "Paddy" , "Fit of bad temper" , "Strip of leather on which razor is sharpened" , "Bad temper - sharpen (a razor)" , "temper tantrum" .)