sputter vs spit out

sputter is a noun but spit out is not a noun.

Word	Noun	Adjective	Verb	Adverb
sputter	Yes	No	Yes	No
spit out	No	No	Yes	No

As verbs, sputter and spit out are synonyms defined as:

Other synonyms of sputter include splutter.

As verbs, spit out is a hypernym of sputter; that is, spit out is a word with a broader meaning than sputter:

Other hypernyms of sputter include cough out, cough up, expectorate, spit up.

sputter (noun)	spit out (noun)
an utterance (of words) with spitting sounds (as in rage)
the noise of something spattering or sputtering explosively

sputter (verb)	spit out (verb)
spit up in an explosive manner	spit up in an explosive manner
cause to undergo a process in which atoms are removed	discharge (phlegm or sputum) from the lungs and out of the mouth
utter with a spitting sound, as if in a rage	utter with anger or contempt
climb awkwardly, as if by scrambling
make an explosive sound