Tantrum (5)
(Other definitions for strop that I've seen before include "Sharpen an old blade" , "Bad temper - sharpen (a razor)" , "Paddy" , "Piece of leather on which razor is sharpened" , "Display of temper" .)
'tantrum' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for paddy that I've seen before include "Rice in the husk" , "One regularly flooded" , "field out East" , "show of anger" , "Wobbly" .)
(Other definitions for temper that I've seen before include "Display of anger" , "(Calm or furious) disposition" , "Lose it and lose control" , "Moderate; ill humour" , "Toughen with anger" .)
(Other definitions for wobbly that I've seen before include "Rickety" , "Unstable - it may be thrown!" , "Swaying unsteadily" , "Unstable - tantrum" , "one may be thrown in temper" .)