Green’s Dictionary of Slang

horse v.

1. [late 16C–17C; 1930s+] to have sexual intercourse.

2. [late 17C–19C] to flog, to whip; thus horsed, held on another person’s back before receiving a flogging [the victim is placed across a wooden frame or ‘horse’].

3. [19C+] (US) to yearn for, to want eagerly, to lust after [? a horse straining at the bit or dial. horse, for a mare to be in heat].

4. in the context of using horse-like strength.

(a) [mid-19C] to work very hard, to work harder than another person.

(b) [20C+] (US) to haul or drag with great effort.

(c) [1920s] to move energetically.

5. to deceive, to cheat.

(a) [mid–late 19C] to swindle, to cheat.

(b) [late 19C–1960s] (US) to trick, to deceive, to tease.

6. [late 19C–1900s] (US campus) to amaze.

7. [late 19C–1910s] (US campus) to study with the help of a translation [horse n. (5a)].

8. see horse around

In phrases

horse around (v.)

1. [20C+] (also horse) to joke, to mess about.

2. [1920s+] (US) to make sexual advances to, to indulge in sexual horseplay.

3. [1960s+] (US) to be keen on becoming married.

horse (it) (v.) (also hoss it) [the strength and stamina of the animal]

[late 19C–1960s] (US) to walk fast.