buy vs repurchase

buy and repurchase both are nouns.

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

As verbs, repurchase is a hyponym of buy; that is, repurchase is a word with a more specific, narrower meaning than buy:

buy (noun)	repurchase (noun)
an advantageous purchase	the act of purchasing back something previously sold

buy (verb)	repurchase (verb)
accept as true	buy what had previously been sold, lost, or given away
obtain by purchase; acquire by means of a financial transaction
make illegal payments to in exchange for favors or influence
acquire by trade or sacrifice or exchange
be worth or be capable of buying