rustling vs murmurous

rustling is a noun but murmurous is not a noun.

Word	Noun	Adjective	Verb	Adverb
rustling	Yes	Yes	No	No
murmurous	No	Yes	No	No

As adjectives, rustling and murmurous are synonyms defined as:

Other synonyms of rustling include soughing, susurrous.

rustling (noun)	murmurous (noun)
the stealing of cattle
a light noise, like the noise of silk clothing or leaves blowing in the wind

rustling (adjective)	murmurous (adjective)
characterized by soft sounds	characterized by soft sounds