nonstarter vs flop

nonstarter and flop both are nouns.

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

As nouns, flop is a hyponym of nonstarter; that is, flop is a word with a more specific, narrower meaning than nonstarter:

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

Other hyponyms of nonstarter include bankrupt, insolvent, flash in the pan, dud, washout, underdog.

nonstarter (noun)	flop (noun)
a horse that fails to run in a race for which it has been entered	the act of throwing yourself down; collapse; sink
a person with a record of failing; someone who loses consistently	a complete failure
	someone who is unsuccessful
	an arithmetic operation performed on floating-point numbers

nonstarter (adverb)	flop (adverb)
	with a flopping sound
	completely