addict

noun

1. A person who is addicted, especially to a harmful drug.

   “a heroin addict”

   “He is an addict when it comes to chocolate cookies.”

   “Those nonaddicts who picked a winning card had increased blood flow to the striatum, but the gambling addicts who picked the right card had much less of it (their reward system was less active).”

   “A stressful environment in which there is ready access to drugs can trump a low genetic risk of addiction in these animals. The same may be true for humans, too. And that’s a notion many find hard to believe: Just about anyone, regardless of baseline genetic risk, can become an addict under the right circumstances.”

2. An adherent or fan (of something).

adj

1. (archaic)Addicted.
2. (obsolete)Bound, tied to, obligated.

verb

1. (Ancient-Rome, transitive)To deliver (someone or something) following a judicial decision.
2. (archaic, reflexive)To devote (oneself) to a given activity, occupation, thing etc.

   “They addict themselves to the civil law.”

   “Having resided some time in this place, we returned to the other country-house which we had left, where lord B— addicted himself so much to hunting, and other male diversions, that I began to think he neglected me […].”

3. (obsolete, transitive)To bind (a person or thing) to the service of something.
4. (obsolete, reflexive)To devote or pledge (oneself) to a given person, cause etc.
5. (archaic, transitive)To devote (one's mind, talent etc.) to a given activity, occupation, thing etc.

   “That part of mankind that addict their minds to speculations.”

6. (transitive)To make (someone) become devoted to a given thing or activity; to cause to be addicted.

   “His genius addicted him to the study of antiquity.”