Green’s Dictionary of Slang

1. drunk.

1801		C. Dibdin Yngr Song Smith 128: Your delicate ladies pretend, you know, / As how they never get muzzy or so.
1890–1904		Farmer & Henley Sl. and Its Analogues.

2. flustered, overcome emotionally.

1844		‘Jonathan Slick’ High Life in N.Y. I 243: I never felt so in all my life – dear me!
1868		H.L. Williams Black-Eyed Beauty 36: Pity she’s so. She’d be a gay card if she’d brighten up a bit.

3. menstruating.

1937–84

Partridge DSUE (1984) 1108/1: mid-C.19–20.

4. pregnant.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1894		G.F. Northall Folk-Phrases of Four Counties 22: She is so. ‘Means a female expects to become a mother’ Huntley. Gloss. of the Cotsworlds, 1868.

5. homosexual.

1910		I.L. Pavia Jahrbuch für sexuelle Zwischenstufen No. 11 41: So = echt, homosexuell, so-party, eine homosexuelle Gesellschaft, so-person = ein Urning, so-woman = eine Urninde [GS].
c.1910		‘X. Mayne’ Intersexes 606: He had not made any confession of homosexuality to Rotenhan, nor had Rotenhan (who was emphatically ‘so,’ but cheerfully untroubled by conscience’s misgivings) said in so many words anything to Platen [GS].
1933		‘K. Bruce’ Goldie 129: ‘I was so!’ he stated with comic emphasis, ‘but I let myself get fat.’.
1946		J. Maclaren-Ross ‘Bitten by the Tarantula’ in Bitten by the Tarantula (2005) 5: Armstrong said, ‘Spider is SO. He writes poetry.’.
1973		J. Justin Prisoner 41: They’re all picking on me because I’m ‘so’.
1976		(con. 1920s) V. King Weeping and Laughter 147: Homosexuals among my bohemians friends were described as ‘so’ (short for sodomy) ‘fairies’ (American) and, especially by the lady-like, ‘pansy’.
1991		(ref. to 1930s) in Porter & Weeks Between the Acts 137: It wasn’t called gay in those days. One used to say, are you ‘so’? Or he’s comme ca, if you were higher up, or TBH (to be had).
2019		P. Baker Fabulosa 298/1: so gay.