Green’s Dictionary of Slang

1. flirtatious talk.

1968

‘Sl. of Watts’ in Current Sl. III:2 43: Smack, n. Love talk or romantic nonsense.

2. nonsense; esp. malicious rumours.

1989		P. Munro Sl. U.
1999		Rosemary Jacobs in San Jose Mercury News 11 May n.p.: Smack (n) – Hurtful gossip or rumors said about an individual, usually started by a jealous person. […].
2000		Ebonics Primer at www.dolemite.com 🌐 smack Definition: nonsense, untruthful or unjustified statements or accusations Example: Yo, why dat nigga be talkin’ smack ’bout my ass?

3. aggressive talk.

1992		R.C. Cruz Straight Outta Compton 48: He was silent while Rachel battered him with a lot of smack.
1999		Eble Campus Sl. Nov. 11: smack – offensive speech.
2010		W.D. Myers Lockdown 150: [G]uys in the hood running down the streets throwing signs and spitting smack .

4. (US campus) rules, regulations, the ‘last word’.

1997–2002

Hope College ‘Dict. of New Terms’ 🌐 smack n. The law, the final work. [...] Usually used in phrases such as ‘I laid the smack down’ or ‘put the smack down’.