Green’s Dictionary of Slang

jag n.1

[dial. jag, as much liquor as one can hold, a ‘load’. Note S.F. Alta 4 Aug. 1889 [title] What a Jag Is: ‘An inquirer asks us the meaning of ‘Jag’ applied to inebriety. It is a new slang. In the rural districts the cargo of a wagon that is hauling wood, when [holding] all that the wagon can carry, is called a ‘load.’ When it is less than up to the full capacity it is called a ‘Jag.’ Therefore when a man is less than dead drunk he has not a load on but merely a Jag’]

1. [late 17C+] a drunken spree; also attrib.; thus get a jag on ; on a jag

2. [late 19C–1940s] a drunkard.

3. [late 19C+] (also jag juice) a drink.

4. attrib. use of sense 3.

5. [late 19C+] (drugs) the consumption of a drug, usu. defined by the drug in question; occas. used of other substances, see cite 1915.

6. [20C+] the experience of taking a specific drug.

7. [20C+] in fig. uses.

(a) (US) a period of indulgence, a fit, a spree of any kind.

(b) (orig. US) a breakdown, an emotional collapse; often as crying jag, lengthy and profound sobbing.

8. [1930s] a hangover.

9. [1950s] a drugs party.

10. [1950s] a trance.

11. [1980s+] the act of injecting oneself with a narcotic drug.

In derivatives

jaggy (adj.)

[late 19C] tipsy, drunk.

In compounds

jag-feeder (n.)

[late 19C–1900s] (US) a drink.

jag juice (n.)

see sense 3 above.

jag line (n.)

[1910s] a police line-up of those arrested as ‘drunk and disorderly’.

jag parlor (n.)

[late 19C-1900s] a bar, a saloon.

jag snakes (n.)

[late 19C] (US) hallucinations from delirium tremens.

In phrases

get a jag on (v.) (also have a jag on)

[late 19C+] to get drunk, to be drunk.

get the jags (v.)

[1900s] to get depressed.

on a jag

1. [late 19C+] on a drunken spree.

2. [1950s+] (orig. US) elated.