Green’s Dictionary of Slang

my man n.

1. an intimate; a very important person.

[Scot]R.L. Stevenson Dr Jekyll & Mr Hyde 9: For my man was a fellow that nobody could have to do with, a really damnable man.
[US] ‘“Hipster” Rev. Dict.’ Mad mag. Oct. 20: pal – my man.
[US]H. Selby Jr Last Exit to Brooklyn 263: How yodoin man? Great Blackie. How’s mah man?
[US]E. Torres Carlito’s Way 11: M’man Polito — went up to 113th Street to straighten a kid out.
[US]D. Woodrell Muscle for the Wing 137: My man over there’ll chew your face off and shit it in your mommy’s roux.
[US]Source Oct. 84: We got Primo. We got Pete Rock. We got my man Lateef.
[US]T. Udo Vatican Bloodbath 8: ‘Whoa,’ he said. ‘Judas here is my man.’.
[US]‘Grandmaster Flash’ Adventures : .

2. (UK black) any male individual irrespective of status or relationship.

[US]W.D. Myers Hoops 17: ‘I’m going to play my man here some one-on-one’.
[US]‘Grandmaster Flash’ Adventures 28: ‘I saw Duck from around the way going corner to corner, trying to pawn what he was holding [...] but they’d all brush him off [...] My man eventually gave up and chucked it out’.
[UK]G. Krauze Who They Was 8: Myman blatantly slammed the door on his own wife’s arm.

In phrases

my man!

(orig. US black) a term of endearment and address between two men.

[US]Down Beat 11 Feb. 16-S: That was Frog — Ben Webster! My man!
[US]N. Heard Howard Street 36: Say, my man, ain’t you Hip’s brother?
[US]‘Iceberg Slim’ Airtight Willie and Me 60: Young Blood, my man!
[US]E. Folb Runnin’ Down Some Lines 246: man, my See ace, n. 1. (form of address between black males that connotes positive feelings between the two).
[UK]J. Cameron It Was An Accident 53: ‘My man!’ he goes. ‘My man!’ I goes. ‘My man!’ he goes. Go on for ever like this.
[UK]N. Griffiths Grits 262: ‘Jerry me man!’ ‘Colm. Ow was that base?’.
[US]A. Steinberg Running the Books 6: Inmates exchange intrixcate handshakes and formal titles: OG, young G, boo, bro, baby boy, brutha, dude, cuz, dawg, P, G, daddy, pimpin’, nigga, man, thug thizzle, my boy, my man, homie.