Green’s Dictionary of Slang

chat v.1

also chat up
[fig. uses of SE; Williams gives 17C examples of chat used euph. for sexual intercourse, e.g. Pepys, Diary 11 Aug. 1663: ‘[the king] hath a chat now and then of Mrs. Stewart.’]

1. [late 19C+] to attempt the first verbal stages of seduction.

2. [20C+] (also chat off) to inform on, to tell on, to reveal.

3. [20C+] thus fig., in non-sexual contexts, to seduce with words.

4. [1910s] (US) to advise, to recommend.

5. [1910s+] (Aus.) to scold.

6. (Aus.) to speak a language.

7. [1950s] to trick verbally, to ‘con’, to persuade.

8. [1960s] (S.Afr.) to kick.

9. [1990s+] to sing rap lyrics.

10. [1990s+] (UK black) to speak, to state.

In phrases

chat down (v.)

[1950s+] (W.I.) to make one’s first advances to a young woman or man in the hope of eventual sexual conquest .

chat shit (v.)

[2010s] (UK black) to talk nonsense; to gossip negatively.

chat someone’s name (v.)

[1950s+] (W.I., Jam.) to gossip maliciously about an absent third party .