Green’s Dictionary of Slang

1. (also flicky) a knife with a spring-loaded blade.

1980		E. Folb Runnin’ Down Some Lines 106: A knife (blade, toothpick, flick, nigger flicker, shank slicer).
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 70/2: flick n. a knife.
2014		Grizzle ‘Mandem Salute’ 🎵 When i roll up on your block i ain’t really tryna back a flicky out.
2016		1011 ‘Next Up?’ 🎵 Get round there samurais and flicks.

2. a razor blade with one side taped so that it can be held as a weapon.

1980

E. Folb Runnin’ Down Some Lines 237: [...] 2. Razor blade with one side heavily taped (used as a weapon).