depressant vs medicinal drug

depressant and medicinal drug both are nouns.

Word	Noun	Adjective	Verb	Adverb
depressant	Yes	Yes	No	No
medicinal drug	Yes	No	No	No

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

depressant: a drug that reduces excitability and calms a person
medicinal drug: (medicine) something that treats or prevents or alleviates the symptoms of disease

Other hypernyms of depressant include drug of abuse, street drug, medicament, medication, medicine.

depressant (noun)	medicinal drug (noun)
a drug that reduces excitability and calms a person	(medicine) something that treats or prevents or alleviates the symptoms of disease

depressant (adjective)	medicinal drug (adjective)
capable of depressing physiological or psychological activity or response by a chemical agent