Green’s Dictionary of Slang

1. to stop someone else achieving their object.

1812

Vaux Vocab. of the Flash Lang. in McLachlan (1964) 268: spoil it: to throw some obstacle in the way of any project or undertaking, so as to cause its failure, is termed spoiling it. In like manner, to prevent another person from succeeding in his object, either by a wilful obstruction, or by some act of imprudence on your part, subjects you to the charge of having spoiled him.

2. to hurt, to bruise; thus spoiled adj., injured.

1821		Egan Life in London (1869) 369: Some sharp words passed, in reply, from Logic, when the dandy, who was rather snuffy as well as impudent, put himself into a posture of defence, crying out, ‘Come on, my fine faelow [sic], I’ll soon spoil your daylights’.
1835		G. Kent Modern Flash Dict. 31: Spoil – to bruise, injure.
1848		Flash Dict. in Sinks of London Laid Open [as cit. 1835].
1886		‘Lady Kate, the Dashing Female Detective’ in Roberts et al. Old Sleuth’s Freaky Female Detectives (1990) 33/2: Was he badly spoiled? [...] The inquiry ‘was he badly “spoiled”?’ meant badly wounded.

3. (US) to kill.

1863

T. Taylor Ticket-Of-Leave Man Act I: He’s taken his oath [...] to be square with me for that Peckham job [...] When I spoiled his mate.

4. in fig. use of sense 3, to finish (a drink); thus spoiled adj., drunk.

1865		Leaves from Diary of Celebrated Burglar 75/2: We had left a considerable quantity of whisky on the table, and [...] the old lady, Jessie and two of her sisters gathered around it and it was ‘spoiled’.
1877		F. Remington letter in Splete Sel. Letters (1988) 14: I can spoil an immense amount of good grub at any time.
c.1943		‘Bill O. Lading’ You Chirped a Chinful!! n.p.: Spoiled: Intoxicated.