Green’s Dictionary of Slang

acid n.1

1. [1960s+] (drugs) LSD, i.e. d-lysergic acid diethylamide-25 [a powerful, synthetic hallucinogen, based on ergot and discovered in 1943 by Dr Albert Hofmann of Sandoz Laboratories, Basel, and massively popularized in 1960s by Dr Timothy Leary (1920–96), Ken Kesey (1935–2001) and his Merry Pranksters, rock groups and the ‘alternative society’].

2. attrib. use of sense 1.

3. [1970s+] (W.I.) rum [joc. allusion to its strength].

4. [1980s–90s] (drugs) MDMA; post-early 1990s usage is historical.

5. [1990s+] (W.I./UK black teen) a special unit of the Jamaican police force, especially feared because of their severe tactics [? SE acid, possible use in torture; or ? acid n.2 ].

In compounds

acid cap (n.) [cap n.4 (2)]

[1970s+] one tablet or capsule of LSD.

acid casualty (n.)

1. [1970s+] one whose brain is deemed to have suffered from an excess of hallucinogens.

2. [1980s+] the victim of an excess of MDMA.

acid flashback (n.)

the recurrence of an LSD trip at some unspecified later date; the experience is assumed to be unpleasant.

acid freak (n.) [-freak sfx]

[1960s+] (drugs) a regular user of LSD.

acid-head (n.) [-head sfx (4)] [1960s+] (drugs)

1. a regular user of LSD.

2. attrib. use of sense 1.

acid house party (n.) [sense 3 above + SE house music + party; post-early 1990s usage is historical]

[1980s–90s] an illegal party, often held in a large building, such as a warehouse, usu. just outside a major city, where thousands of young people pay for entrance, dance to house music and, allegedly, consume MDMA and other illegal drugs.

acid pad (n.) [pad n.2 (2)]

[1960s+] (US drugs) a place where LSD is consumed.

acid rapper (n.) [fig. use of rapper n.2 (6)]

[1960s+] (drugs) one who takes extra-large doses of LSD.

acid rock (n.)

[1960s+] a musical style allegedly influenced by, and purporting to recreate the sensations of, LSD and similar psychedelics; orig. in 1960s but underwent a minor revival in 1980s.

acid test (n.) [SE test; a pun on SE, accentuated by the contemporary slogan Can you pass the acid test? as a form of initiatory challenge. The original ‘acid test’ party, held in a San Francisco dancehall, was arranged by Ken Kesey’s Merry Pranksters group; the participants took LSD, many for the first time, and the event can be seen as the birth of widespread consumption of LSD]

[1960s] a party.

acid trip (n.) [trip n.4 (1)] [1960s+]

1. the experience, often characterized as a ‘journey’, of taking a hallucinogenic drug, esp. LSD.

2. a dose of LSD.

In phrases

fire the acid (v.)

[1970s+] (W.I.) to drink rum.

new acid (n.)

[1970s+] (drugs) phencyclidine.

paper acid (n.)

[1960s+] (drugs) LSD, esp. when dropped onto a square of blotting-paper, or when combined with another drug.

super acid (n.)

[1980s+] (drugs) ketamine.