medicine vs operate on

medicine is a noun but operate on is not a noun.

Word	Noun	Adjective	Verb	Adverb
medicine	Yes	No	Yes	No
operate on	No	No	Yes	No

medicine (noun)	operate on (noun)
the learned profession that is mastered by graduate training in a medical school and that is devoted to preventing or alleviating or curing diseases and injuries
punishment for one's actions
(medicine) something that treats or prevents or alleviates the symptoms of disease
the branches of medical science that deal with nonsurgical techniques

medicine (verb)	operate on (verb)
treat medicinally, treat with medicine	perform surgery on