Green’s Dictionary of Slang

nut n.2

[nuts adj.]

1. [mid-19C+] (orig. US, also nuts) an insane person.

2. [20C+] (US campus) an unpopular student.

3. [20C+] (orig. US) a fan, an enthusiast, an obsessive; usu. in defining comb., e.g. cricket nut, computer nut.

4. [20C+] (orig. US) a course of action, an obsession.

5. [1930s] (US Und.) a beggar who is insane, or poses as such.

In derivatives

nuttery (n.)

[2000s] insanity; stupidity.

In phrases

be a nut about (v.) (also ...at, ...for, ...on)

[1920s+] to be enthusiastic about or expert in.

have a nut on (v.)

[20C+] to be obsessed with.

Pertaining to madness or eccentricity, of people

In compounds

nutbag (n.)

[1990s+] (US) a mentally unstable person.

nutball

see separate entries.

nutbar (n.) (also nutbucket)

[1970s+] (US) a lunatic.

nut-boy (n.)

[1990s+] (US) a madman, an eccentric.

nutburger (n.)

[1980s+] (US) a lunatic.

nutcake (n.)

[1960s+] (US) a fool, a lunatic, an eccentric.

nutcase

see separate entries.

nut doctor (n.) (also nut doc)

[1930s+] (orig. US) a psychiatrist.

nuthead (n.) (also nutbrain) [-head sfx (1)]

[1910s+] (orig. US) a fool, a simpleton; thus nutheaded adj.

nut-job (n.) [job n.2 (2)]

[1950s+] (US) a lunatic or very eccentric person; also attrib.

nut-nut (n.) [redup.]

[2000s] an insane, eccentric person.

nut role

see separate entries.

nut roll (n.) [pun on the sweet]

[1990s+] (US black) an eccentric or mad person.

nut wagon (n.) (also nut train)

[1960s] (US) a state of madness, psychosis.

Pertaining to madness or eccentricity, of institutions

In compounds

nut alley (n.)

[1930s] (US prison) the prison insane ward.

nutbox (n.)

[1960s+] (US) a psychiatric institution.

nut college (n.)

[late 19C–1960s] (US) a lunatic asylum/psychiatric institution.

nut factory (n.)

[late 19C+] (Aus./US) a psychiatric institution.

nut farm (n.)

[1930s–70s] (US) a psychiatric institution.

nut foundry (n.)

[1900s–40s] (US) a psychiatric institution.

nut hatch (n.) [? underpinned by the well-known asylum at Colney Hatch near London, opened in 1851]

[1940s+] (orig. US) a psychiatric institution.

nut house (n.)

see separate entry.

nut hut (n.)

[1990s+] a psychiatric institution.

nut place (n.)

[1960s+] (US) a psychiatric institution.

nut ward (n.)

1. [20C+] (US) a psychiatric unit.

2. attrib. use of sense 1.

nut wing (n.)

[1990s+] (US prison) the psychiatric wing.

In phrases

nuts and sluts (n.)

[1970s+] (US campus) a course in abnormal psychology.

on the nut

[1960s] being insane, or posing as such.