Green’s Dictionary of Slang

1. a close friend; also attrib.

1956		‘Ed Lacy’ Men from the Boys (1967) 31: Bill Ash had been my boon buddy for a lot of years.
1960		G. Swarthout Where the Boys Are 108: Nex’ Tuesday night my lil’ boons we go into action for causa freedom and democracy!
1972		Dahlskog Dict. Contemp. and Colloq. Usage.
1973		A. Childress Hero 22: You see me, you see him. He was my boon! [HDAS].

2. a black person [? ace boon coon n. (1)].

1967–68		in DARE.
1979		in L. Bangs Psychotic Reactions (1988) 272: ‘All the boons just sat there laughing at me.’ ‘Boons,’ I said. ‘What’s boons?’ ‘You know [...] Black guys.’ ‘Why do you call them that?’ ‘I dunno. From “baboons”, I guess.’.
1982		(con. 1970) J.M. Del Vecchio 13th Valley (1983) 86: ‘If it aint Bro Boon,’ Egan laughed [...] ‘Is that Bro Boon like in Bro Coon,’ Jax intonated with mock arrogant disgust.
2005		R. Cea No Lights, No Sirens 229: Rob, I just tossed someone. I ain’t sewered it yet. Give it to the little boon and let’s do our work.