Green’s Dictionary of Slang

brain n.1

1. [mid-19C+] (orig. US Und., also brain guy, brains) a planner, an ‘ideas man’, a mastermind, i.e. planning a bank raid but not participating in the actual action; often found in fiction as The Brain or The Brains.

2. [1910s–80s] (orig. US, also brains) in non-criminal use of sense 1.

3. [1910s+] (orig. US, also brains) an intellectual, an intelligent person, esp. one who is unpleasantly, anti-socially intellectual; also in ironic use.

4. [1940s] (US Und., also brain box) the combination of a safe.

5. [1980s] (US campus) in ironic reversal, a stupid person.

6. [2010s] (US black) fellatio.

SE in slang uses

In compounds

brain box (n.)

see sense 4 above.

brain bucket (n.)

1. [mid-19C–1910s] (US, also brain barrel) the head, the skull.

2. [1950s+] a protective helmet, whatever its use.

brain-burners (n.)

[1970s] (US drugs/gay) amphetamines when taken intravenously.

brain burp (n.) [the spontaneity of an explosion of wind]

1. [1990s+] (US campus) a random thought.

2. a brief instance of mental dysfunction.

brain-canister (n.)

[mid-19C] (orig. boxing) the head.

brain capsule (n.) [the supposedly stimulating properties of nicotine]

[1900s] (US) a cigarette.

brainchild (n.)

[1960s+] (US) a very intelligent person.

brain college (n.) [ironic use]

[late 19C] (US) a lunatic asylum.

brain damage (n.) [its supposed effects]

1. [1990s+] beer, or any strong intoxicating drink.

2. [2000s] (drugs) heroin.

brain dead

see separate entries.

brain drain (n.)

[1960s+] the emigration of highly qualified people, generally scientists and academics, from a country (e.g. Britain) in search of more prestigious jobs, better facilities for research and higher salaries.

brain drainer (n.)

[1960s] (Aus.) a university.

brain fart

see separate entries.

brain guy (n.)

see sense 1 above.

brainless wonder (n.) (also fuckless wonder) [SE brainless + wonder, an outstanding specimen of something + ? play on a carnival attraction, the ‘Boneless Wonder’]

[late 19C+] (US) a fool, a scatter-brained person; a stupid thing.

brainpan (n.) [SE brain-pan, that which contains the brain, the skull]

1. [late 15C+] the human head.

2. [17C+] the mind.

brain-pot (n.)

[mid-19C-1900s] the skull, the head.

brain salad surgery (n.) [pun on head n. (2c)]

[1990s+] (US) fellatio.

brainstem (n.) [SE brainstem, ‘the central trunk of the brain upon which the cerebrum and cerebellum are set, and which continues downwards to form the spinal cord’ (OED)]

[1980s] (US campus) an eccentric.

brainstorm (n.) [ext. of SE use; popularized by the murder trial of society architect Harry Thaw in 1906–8, during which his lawyer claimed he had suffered a ‘brain storm’]

1. [20C+] (orig. US) a sudden inspiration or bright idea; thus brainstorming.

2. [1910s+] a nervous breakdown, a physical or emotional collapse.

brain tablet (n.) [the supposedly stimulating properties of nicotine]

[1900s-30s] (US) a cigarette.

brain ticklers (n.) [amphetamine accelerates the activity of the central nervous system and thence the brain]

[1960s+] (drugs) amphetamines.

brainwave (n.)

[late 19C+] a sudden inspiration or bright idea.

In phrases

do someone’s brain in (v.)

[1980s+] to drive mad, to exasperate.

fuck someone’s brains out (v.) (also hump someone’s brains out, ball/fuck one’s brains out, fuck the brains out of someone) [fuck v. (1)/ball v.3 /hump v.1 (1)]

[1950s+] to copulate very strenuously and poss. sadistically, usu. of a man to a woman.

get up off one’s brains (v.)

[1950s] (Aus.) to be motivated.

on the brain

[late 19C] thinking.

out of one’s brain(s) (adj.) (also off one’s brain(s), out of one’s cranium)

1. [1940s+] intoxicated with drugs, or alcohol; thus go off one’s brain.

2. [1960s+] mad, crazy; thus go off one’s brain, to go mad, to lose emotional control.

3. [1990s+] overwhelmed.