cough up vs splutter

cough up is not a noun while splutter is a noun.

Word	Noun	Adjective	Verb	Adverb
cough up	No	No	Yes	No
splutter	Yes	No	Yes	No

As verbs, splutter is a hyponym of cough up; that is, splutter is a word with a more specific, narrower meaning than cough up:

Other hyponyms of cough up include cough, ptyalise, ptyalize, spew, spit, spue, spit out, sputter.

cough up (noun)	splutter (noun)
	an utterance (of words) with spitting sounds (as in rage)
	the noise of something spattering or sputtering explosively

cough up (verb)	splutter (verb)
discharge (phlegm or sputum) from the lungs and out of the mouth	spit up in an explosive manner
give reluctantly	utter with a spitting sound, as if in a rage