subscribe vs buy

subscribe is not a noun while buy is a noun.

Word	Noun	Adjective	Verb	Adverb
subscribe	No	No	Yes	No
buy	Yes	No	Yes	No

As verbs, buy is a hypernym of subscribe; that is, buy is a word with a broader meaning than subscribe:

Other hypernyms of subscribe include purchase.

subscribe (noun)	buy (noun)
	an advantageous purchase

subscribe (verb)	buy (verb)
mark with one's signature; write one's name (on)	accept as true
adopt as a belief	obtain by purchase; acquire by means of a financial transaction
receive or obtain regularly	make illegal payments to in exchange for favors or influence
offer to buy, as of stocks and shares	acquire by trade or sacrifice or exchange
pay (an amount of money) as a contribution to a charity or service, especially at regular intervals	be worth or be capable of buying