dud vs nonstarter

dud and nonstarter both are nouns.

Word	Noun	Adjective	Verb	Adverb
dud	Yes	Yes	No	No
nonstarter	Yes	No	No	No

As nouns, nonstarter is a hypernym of dud; that is, nonstarter is a word with a broader meaning than dud:

dud: someone who is unsuccessful
nonstarter: a person with a record of failing; someone who loses consistently

Other hypernyms of dud include failure, loser, unsuccessful person.

dud (noun)	nonstarter (noun)
an event that fails badly or is totally ineffectual	a horse that fails to run in a race for which it has been entered
an explosion that fails to occur	a person with a record of failing; someone who loses consistently
someone who is unsuccessful

dud (adjective)	nonstarter (adjective)
failing to detonate; especially not charged with an active explosive