shwa vs murmur

shwa and murmur both are nouns.

Word	Noun	Adjective	Verb	Adverb
shwa	Yes	No	No	No
murmur	Yes	No	Yes	No

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

Other hyponyms of shwa include murmur vowel.

shwa (noun)	murmur (noun)
a neutral middle vowel; occurs in unstressed syllables	a complaint uttered in a low and indistinct tone
	a schwa that is incidental to the pronunciation of a consonant
	a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech
	an abnormal sound of the heart; sometimes a sign of abnormal function of the heart valves

shwa (verb)	murmur (verb)
	speak softly or indistinctly
	make complaining remarks or noises under one's breath