Green’s Dictionary of Slang

jagger n.2

1. (US carnival) a tattoo artist.

[US]J.E. Dadswell Hey, Sucker 87: Other interesting words in daily use are: jagger for tattoo artist; duker for fortune teller; glittergals for girl-shows performers; tinsel-molls for the painted ladies of the tenderloin.

2. a heroin user [jag v.1 (4)].

[UK] Indep. Rev. 19 July 1: Methadone, prescribed by GPs, is now the orthodox medical treatment for the 8,500 ‘jaggers’ who have turned Glasgow into Europe’s heroin capital.