Green’s Dictionary of Slang

plant n.

[plant v.1 (1)]

1. [late 18C+] (orig. UK Und.) a hiding place for stolen goods; thus the goods themselves.

2. [late 18C+] a swindle, a fraudulent trick.

3. [early 19C–1930s] any form of criminal activity.

4. [mid-19C] a hiding place for burglary tools.

5. [mid-19C] a hiding place for illegally acquired money; cit. 1931–4 refers to money that is not stolen, but the possession of which contravenes prison rules.

6. [mid-19C] a person targeted for robbery.

7. a slander.

8. [mid-19C+] a detective, a spy, a decoy, esp. one who works under cover in a criminal gang; also any undercover police activity.

9. [mid-19C+] (UK/US Und./police) a trap; often in the form of an item that is deliberately left vulnerable and under surveillance, e.g. a briefcase, in the hope that a thief will pick it up; occas. used of the act placing such an object.

10. [mid-19C–1900s] (US) one’s home.

11. (US) a buried corpse.

12. [late 19C–1940s] (UK/US Und.) a place targeted for a crime, e.g. a bank.

13. [1900s] (US) a venue, e.g. to display one’s wares.

14. [1900s] a site where a street-seller is established.

15. [1900s] (US) a casino, a gambling den.

16. [1910s] a hiding place for a person.

17. [1910s–40s] (UK Und.) the manufacture and selling of counterfeit money.

18. [1920s–50s] a trick, a tease.

19. [1920s+] (orig. US) someone who has been deliberately placed in an environment, typically an audience, where they respond (ostensibly as just another punter) to a call from the stage for ‘volunteers’.

20. [1920s+] (drugs) a hiding place for drugs or drug-taking equipment; thus the drugs or equipment thus hidden.

In phrases

in plant (adj.)

[early–mid-19C] (Aus.) hidden away.

prime plant (n.) [prime adj.]

[mid-19C] (UK Und.) a potential victim, as assessed by a villain.

rise a plant (v.)

[early 19C] (UK Und.) of a thief, to unearth some loot from where it has been hidden by them or by another thief.

spring a plant (v.) [spring v. (3) ]

[19C] (UK Und.) to uncover a hiding place, usu. one which another villain uses for their plunder.