Green’s Dictionary of Slang

alligator n.

[SE alligator, based on characteristics of the animal, e.g. gaping jaws, aggressiveness and lack of speed]

1. [early–mid-19C] a singer who opens their mouth wide.

2. [mid–late 19C] a herring; a sardine.

3. [mid-19C–1940s] a worthless, unpleasant person.

4. [mid-19C+] (Aus./US) an old and/or slow horse.

5. [late 19C+] (US) a native of Florida [the state’s indigenous animal].

6. [20C+] (US) any sexually aggressive male.

7. [1910s] (Aus.) an aggressive, tough person.

8. [1910s–70s] (US) a chatterbox, a ‘big mouth’.

9. [1930s–50s] a person, usu. non-black, who listens to and appreciates jazz, but does not play; orig. dismissive [the jazz musicians’ ref. to someone who ‘swallowed up’ everything on offer, ? coined by Louis Armstrong (1901–71) to describe white musicians who pirated the original ideas created by their black peers; ‘We’d call them alligators…because they were the guys who came to swallow everything we had to learn’].

10. [1950s] (US black) a white jazz musician [see sense 9].

11. [1950s] (US teen) any person, irrespective of musical taste.

12. see gator n.2 (2)

In compounds

alligator bull (n.) [SE alligator (there are none in Aus.) + bull n.6 (1)]

[1940s] (Aus.) nonsense, rubbish.

alligator cigarette (n.)

[1940s] (US drugs) a marijuana cigarette.

alligator (horse) (n.)

[19C] (US) a tough man, usu. used of a Kentucky frontiersman.

Alligatorland (n.) [sense 4 above: Queensland has a lot of horses]

[late 19C-1910s] (Aus.) Queensland.

alligator mouth (n.)

[1950s+] (US) a descriptive term for the mouth of a boaster, a braggart, someone with an inclination to boast or brag but insufficient courage to back up their words; such a person is usu. described in the extended phr. (he’s got) an alligator mouth and a hummingbird/canary ass; note don’t let your (alligator) mouth overload your ass(hole) under mouth n.

SE in slang uses

In compounds

alligator bait (n.)

1. [late 19C-1960s] a black person, usu. a child [image of racist whites lynching blacks and tossing them to the alligators and f. the practice of Southern whites, who found it amusing to threaten such children with ‘throwing them to the alligators’].

2. [1900s–60s] (US) any inedible food, esp. liver [the practice in early 20C US construction camps of letting bull’s liver rot before cooking it; the meat was thus tenderized, but simultaneously rendered too foul for any human to eat].

3. [1910s–50s] (US) a worthless, unpleasant person, of any race.

4. [1940s] (US) a derog. term for a black native of Florida.

In phrases

don’t let the alligator beat you to the pond

[1930s] (US black) don’t be slow(witted) or you will be out-done.