Green’s Dictionary of Slang

1. urine.

1937–84		Partridge DSUE (1984) 1008/2: C.17–18.
1949		Monteleone Criminal Sl. (rev. edn).

2. tears.

1829

D. Jerrold Black-Ey’d Susan I ii: Avast with your salt water!

3. a sailor; also attrib.

1830		W.H. Williams Wreck II ii: You must excuse their salt-water manners.
1839		(con. 1703) W.H. Ainsworth Jack Sheppard (1840) 63: Get ashore, give old saltwater your fare.
1929		R.H.H. Nichols ‘Sinbad the Sailor’ in Fight Stories Jan. 🌐 You lousy saltwater bum.

4. (US black) alcohol.

c.1929

Charley Patton ‘Revenue Man Blues’ 🎵 Oh, a doney loves her saltwater, well, she always wants a drink.