Green’s Dictionary of Slang

1. (Irish) drunk.

1832		S. Lover Legends and Stories 190: Oh, the hangin’ bone villain!
1997		Share Slanguage.

2. (US campus) feeling ill, esp. hungover.

1971		Current Sl. VI.
1996		Eble Campus Sl. Mar. 4: hanging – experiencing the ill effects of excessive drinking: ‘On the morning after my twenty-first birthday I was hanging hard’.
2004		P. Howard PS, I Scored the Bridesmaids 190: I don’t know what they put in those My First Lagers, but I’m totally hanging this morning.

3. (Irish drugs) in need of a narcotic drug.

2015

L. McInerney Glorious Heresies 301: The chance of instant gratification faded into another night of hurried phone calls and bitten nails. ‘I’m kinda hanging, like’.