Niffie is an old Dutch street-slang word used to refer to a knife. It appeared mainly in older
street culture and youth slang before modern slang terms became popular. The word is used in informal situations, often with a playful or slightly cautionary tone.
Etymology:
Derived from the English word knife. In
street slang, knife shifted to nife → nif → niffie, with the “-ie” ending adding a typical Dutch informal sound.