Green’s Dictionary of Slang

ginger n.1

[SE ginger, f. the colour or spiciness]

1. [early–mid-19C] a showy, fast horse.

2. [early 19C+] a red-haired or sandy-haired person; also as adj.

3. [mid-19C+] high spirits, verve, vigour.

In phrases

give someone ginger (v.)

[1920s] to treat brusquely, to ‘make someone jump’.

like ginger (adv.)

[late 19C] to a great extent.

In exclamations

ginger!

excl. used when touching something hot.

that’s the ginger!

[mid-19C] (US) excl. of approval, encouragement.