drug addiction vs habituation

drug addiction and habituation both are nouns.

Word	Noun	Adjective	Verb	Adverb
drug addiction	Yes	No	No	No
habituation	Yes	No	No	No

As nouns, habituation is a hypernym of drug addiction; that is, habituation is a word with a broader meaning than drug addiction:

drug addiction: an addiction to a drug (especially a narcotic drug)
habituation: being abnormally tolerant to and dependent on something that is psychologically or physically habit-forming (especially alcohol or narcotic drugs)

Other hypernyms of drug addiction include addiction, dependance, dependence, dependency.

drug addiction (noun)	habituation (noun)
an addiction to a drug (especially a narcotic drug)	a general accommodation to unchanging environmental conditions
	being abnormally tolerant to and dependent on something that is psychologically or physically habit-forming (especially alcohol or narcotic drugs)