Green’s Dictionary of Slang

(US black/teen) a var. of bitch n.¹ ; can be used to refer to a male or a female, a friend or an enemy, as an excl. etc.

1988		Too $hort ‘Cusswords’ 🎵 Too $hort, don’t say it tonight, beeatch.
1997		Da Bomb Summer Supplement 2: Biatch (n. & voc.) {Mildly vulgar} bitch. This term is used among friends to replace a name.
1997–2000		College Sl. Research Project (Cal. State Poly. Uni., Pomona) 🌐 B-ei-ei-ich (noun) Bitch. [Ibid.] Beeyatch (Byach—pronounced ‘BEE-YOCH’) (noun and vocative) 1. An exclamatory response to a girl that dissed ya or used to describe a chick that ain’t worth mugging with. [...] 2. (noun) An attractively fine lady, especially with an attitude. [...] 3. (noun and vocative) It’s used to dis everyone (its not aimed towards women); a jerk. 4. (noun and vocative) Said to a friend when they tell you something outrageous.
1998		Source Nov. 137: Ever since the cleansing ceremony [...] B-Real cut down on the beatches-n-booze.
2000		Ebonics Primer at www.dolemite.com 🌐 biatch Definition: woman, one that is currently dating the person speaking Example: Lacretia my biatch, so git yo own ho diggity ho bag. [Ibid.] be-i-itch Definition: a homie that be trippin’ or illin’ Example: You is a be-i-itch!!
2001		Eble Campus Sl. Fall 3: crack-whore – person unworthy of respect or esteem. Also bee-otch.
2002		‘Touré’ Portable Promised Land (ms.) 161: We Words (My Favorite Things) [...] Booshit. Summbitch. Beeatch. Shimit. Gotdamn.
2003		Eble Campus Sl. Nov. 1: bia – from biatch.
2004		T. Fey Mean Girls [movie script] ‘Trang Pak is a grotsky little byotch’.
2008		T. Dorsey Atomic Lobster 22: I’m taller than you, bee-ach.