die vs buy it

die is a noun but buy it is not a noun.

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

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

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

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

die (noun)	buy it (noun)
a small cube with 1 to 6 spots on the six faces; used in gambling to generate random numbers
a device used for shaping metal
a cutting tool that is fitted into a diestock and used for cutting male (external) screw threads on screws or bolts or pipes or rods

die (verb)	buy it (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life	be killed or die
disappear or come to an end
suffer spiritual death; be damned (in the religious sense)
stop operating or functioning
lose sparkle or bouquet
to be on base at the end of an inning, of a player
cut or shape with a die
be brought to or as if to the point of death by an intense emotion such as embarrassment, amusement, or shame
languish as with love or desire
feel indifferent towards
suffer or face the pain of death