drug user vs addict

drug user and addict both are nouns.

Word	Noun	Adjective	Verb	Adverb
drug user	Yes	No	No	No
addict	Yes	No	Yes	No

As nouns, addict is a hyponym of drug user; that is, addict is a word with a more specific, narrower meaning than drug user:

Other hyponyms of drug user include head, tripper.

drug user (noun)	addict (noun)
a person who takes drugs	someone who is physiologically dependent on a substance or activity
	someone who is so ardently devoted to something that it resembles an addiction

drug user (verb)	addict (verb)
	to cause (someone or oneself) to become dependent (on something, especially a narcotic drug)