Definitions
1.nounA strap; more specifically a piece of leather or a substitute (notably canvas), or strip of wood covered with a suitable material, for honing a razor, in this sense also called razor strop.
2.nounA bad mood or temper (see stroppy.)
3.nounA piece of rope spliced into a circular wreath, and put round a block for hanging it.
4.nounA poor-quality or unsaleable diamond.