Green’s Dictionary of Slang

possum n.

1. [late 19C] (US) a coward [one of the animal’s characteristics is feigning death when threatened].

2. [late 19C+] (also opossum) a person (used either affectionately or derog.).

3. [1920s+] (Aus.) a fraudulent substitution [play on SE ring-tail possum (Pseudocheirus peregrinus) + ring in v.1 (1)].

4. [1900s] (US) a black person.

5. [1920s+] (Aus.) a fool, esp. a trickster’s victim; sometimes intensified as posso-de-luxe n.

SE in slang uses

In compounds

possum-belly (n.) [thus used for similar arrangements on livestock and circus wagons]

1. [19C–1940s] ‘a baggy, dried cowhide fastened horizontally beneath the wagon box and used for carrying a reserve of fuel’ (P.A. Rollins, Gone Haywire, 1939); also as a term of abuse.

2. [1920s–40s] (US tramp) to ride under a railroad car.

possum-eater (n.) [their supposed diet]

[1900s–60s] (Aus.) a peasant, a country bumpkin; thus possum-eating, countrified.

possum fucker (n.) [fucker n. (1)]

[2000s] (Aus.) a country-dweller, a peasant.

possum-guts (n.) [reflecting a low opinion of the animal]

1. [mid–late 19C] (Aus.) a general term of abuse.

2. [1950s–60s] (Aus.) a coward; thus possum-gutted adj., cowardly.

possum-rider (n.)

[1990s+] (US campus) a promiscuous person.

possum-scoffer (n.) [scoff v. (1)]

[late 19C] a Native Australian.

In phrases

come possum (v.)

1. [mid-19C] (US) to act in a deceptive manner.

2. see also under come the... v.

like a possum up a gum-tree (adv.)

[late 19C–1950s] (Aus.) absolutely contentedly, perfectly happily.

stir the possum (v.) (also rouse the possum) [the animal’s habit of keeping quite still for long periods]

[late 19C+] (Aus.) to create a disturbance, to start things moving, to jolt the general apathy.