n. A knife. Usually associated with a makeshift instrument fashioned from something not normally used as a weapon (like a plastic spoon or a toothbrush).n. A woody by-product from processing flax or hemp.n. A shim, i.e. a small library that transparently intercepts and modifies calls to an API, usually for compatibility purposes.v. To stab someone with a shiv.v. By extension, to stab someone with anything not intended as a stabbing weapon.