flash in the pan vs nonstarter

flash in the pan and nonstarter both are nouns.

Word	Noun	Adjective	Verb	Adverb
flash in the pan	Yes	No	No	No
nonstarter	Yes	No	No	No

As nouns, nonstarter is a hypernym of flash in the pan; that is, nonstarter is a word with a broader meaning than flash in the pan:

flash in the pan: someone who enjoys transient success but then fails
nonstarter: a person with a record of failing; someone who loses consistently

Other hypernyms of flash in the pan include failure, loser, unsuccessful person.

flash in the pan (noun)	nonstarter (noun)
someone who enjoys transient success but then fails	a horse that fails to run in a race for which it has been entered
	a person with a record of failing; someone who loses consistently