addict vs junky

addict and junky both are nouns.

Word	Noun	Adjective	Verb	Adverb
addict	Yes	No	Yes	No
junky	Yes	No	No	No

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

Other hyponyms of addict include caffein addict, caffeine addict, drug addict, junkie, speed freak.

As nouns, addict and junky are synonyms defined as:

addict and junky: someone who is so ardently devoted to something that it resembles an addiction

Other synonyms of addict include freak, junkie, nut.

addict (noun)	junky (noun)
someone who is physiologically dependent on a substance or activity	a narcotics addict
someone who is so ardently devoted to something that it resembles an addiction	someone who is so ardently devoted to something that it resembles an addiction

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