expire vs buy it

expire and buy it both are verbs.

Word	Noun	Adjective	Verb	Adverb
expire	No	No	Yes	No
buy it	No	No	Yes	No

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

expire: pass from physical life and lose all bodily attributes and functions necessary to sustain life
buy it: be killed or die

Other hyponyms of expire include abort, asphyxiate, stifle, suffocate, pip out, drown, predecease, famish, starve, fall, succumb, yield.

expire (verb)	buy it (verb)
expel air	be killed or die
pass from physical life and lose all bodily attributes and functions necessary to sustain life
lose validity