die vs succumb

die is a noun but succumb is not a noun.

Word	Noun	Adjective	Verb	Adverb
die	Yes	No	Yes	No
succumb	No	No	Yes	No

As verbs, succumb is a hyponym of die; that is, succumb 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
succumb: be fatally overwhelmed

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

die (noun)	succumb (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)	succumb (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life	consent reluctantly
disappear or come to an end	be fatally overwhelmed
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