junky vs crack addict

junky and crack addict both are nouns.

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

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

Other hyponyms of junky include cocaine addict, binger, heroin addict, opium addict, opium taker, withdrawer.

junky (noun)	crack addict (noun)
a narcotics addict	someone addicted to crack cocaine
someone who is so ardently devoted to something that it resembles an addiction