Green’s Dictionary of Slang

1. (US campus) the small loop (ostensibly for hanging the shirt when no hanger is available) on the upper back of many shirts; such a loop, supposedly, can be used to hold a victim ready for buggery (cf. fairy loop under fairy n.¹ ).

1984		J. Grahn Another Mother Tongue 81: This tag, used for hanging up the shirt, is called a ‘fruit loop.’.
1989		Kirk & Madsen After the Ball 21: The ‘fairy hook’ or ‘fruit loop’ found on the back of some shirts.
2002		J.W. Ware North Shore Story 67: [He] put on a blue button down shirt with the fruit-loop still attached in back.
2008		T. Gouin Coco-Colored Boy 111: ‘I bet you got a fruit loop shirt on tonight, don’t you Billy?’ laughed Dicky.

2. (US) a homosexual man or woman.

1989		‘Captain X’ & Dodson Unfriendly Skies 158: Many of these guys [i.e. flight attendants] have to take a lot of ribbing [...] ‘Great Airborne Fruit Loops’ [HDAS].
2006		T.C. West Disruptive Christian Ethics 65: A Latina lesbian, ‘a fruit loop’ over whom he had power.
2007		‘Noire’ Thong on Fire 105: For all I cared, them patty-cake, fruit-loop niggas coulda drilled each other.

3. (US gay) a freedom ring, one of a set of six metal rings in the colours of the rainbow worn to indicate that one is homosexual or sympathetic to homosexual causes.

1998

R. Scott Rebecca’s Dict. of Queer Sl. 🌐 fruit loop(s) — 1) slang for freedom rings.

4. a homosexual pick-up or cruising area .

1994		K. Dilallo Unofficial Gay Manual 91: Those versed in such esoterica recognize it as Dupont Circle (aka the Fruit Loop).
2004		J. Campbell USA et al. 310: Godfrey’s (308 E Grace St) and Barcode (6 E Grace St) are part of a circle of gay bars along Grace St, affectionately known as the fruit loop.

5. a derog. term for a group of homosexuals.

1991

J. O’Shea Daisy Chain 229: A ring of homosexual attorneys that the Texans dubbed the Fruit Loop.