Green’s Dictionary of Slang

leather adj.

[1960s+] (orig. US gay) pertaining to leather fetishism in attire and behaviour.

In compounds

leather bar (n.) (also leather lounge)

[1960s+] (orig. US gay) a bar frequented by leather fetishists and sadomasochistic male homosexuals.

leather boy (n.) (also leather man, leather job)

[1960s+] (gay) a male leather fetishist homosexual.

leather dyke (n.) [dyke n.]

[1990s+] (gay) a lesbian leather fetishist.

leather freak (n.) [-freak sfx]

[1960s+] (US) a leather fetishist.

leather queen (n.) (also leather Mary) [-queen sfx (2)/Mary n. (2a)]

[1960s+] (orig. US gay) a male homosexual who likes dressing in leather and may also enjoy sadomasochism; also attrib.

SE in slang uses

In compounds

leather bum (n.)

[20C+] a civil servant who is totally dedicated to work and thus never leaves their desk.

leather-face (n.)

[mid–late 19C] (US) an emotionless face or the individual with such a face; thus leather-face(d) adj.

leatherhead (n.)

see separate entry.

leather medal (n.) [a ‘real’ medal is metal]

[early 19C–1940s] (US) a fig. medal for failure, laziness, the booby prize.

leatherneck (n.)

see separate entry.

leather piece (n.)

[1960s+] (US black) any garment, esp. a coat, made of leather.

leatherskin (n.)

[mid–late 19C] (US) a derog. name for a Native American; thus leather-skinned adj.

In phrases

all leather (adj.) [the toughness and durability of leather]

[1920s] of a person, dependable, trustworthy.