strop: [OE] Strop has now narrowed down in meaning to the specialized ‘strip of leather for sharpening a razor’, but it used to be a much more general term for a leather band or loop. It goes back to a prehistoric West Germanic word that was probably an adoption of Latin stroppus ‘strap, band’. That in turn may well have come from Greek strophos ‘twisted band’, from strephein ‘turn’.
Old French had estrope from the same West Germanic source, and that probably reinforced the English word in the 14th century. Scottish pronunciation turned strop into strap [17], and that has now inherited most of the general functions of strop in English at large. As for stroppy ‘bad-tempered and uncooperative’, first recorded in 1951, no convincing link with strop ‘leather strip’ has ever been established (strop ‘fit of stroppiness’ is a back-formation from stroppy).
One suggestion is that it may be a radically stripped-down version of obstreperous.
