antiemetic vs medicinal drug

antiemetic and medicinal drug both are nouns.

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

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

antiemetic: a drug that prevents or alleviates nausea and vomiting
medicinal drug: (medicine) something that treats or prevents or alleviates the symptoms of disease

Other hypernyms of antiemetic include medicament, medication, medicine.

antiemetic (noun)	medicinal drug (noun)
a drug that prevents or alleviates nausea and vomiting	(medicine) something that treats or prevents or alleviates the symptoms of disease