1. 吸毒成瘾者；瘾君子
A junkie is a drug addict.

2. 对…上瘾的人；迷恋…的人
You can use junkie to refer to someone who is very interested in a particular activity, especially when they spend a lot of time on it.

1. someone who is so ardently devoted to something that it resembles an addiction

e.g. a golf addict
a car nut
a bodybuilding freak
a news junkie

Synonym: addictnutfreakjunky

2. a narcotics addict

Synonym: drug addictjunky