Austro-Asiatic vs Munda-Mon-Khmer

Austro-Asiatic and Munda-Mon-Khmer both are nouns.

Word	Noun	Adjective	Verb	Adverb
Austro-Asiatic	Yes	No	No	No
Munda-Mon-Khmer	Yes	No	No	No

As nouns, Austro-Asiatic and Munda-Mon-Khmer are synonyms defined as:

Austro-Asiatic and Munda-Mon-Khmer: a family of languages spoken in southern and southeastern Asia

Other synonyms of Austro-Asiatic include Austro-Asiatic language.

Austro-Asiatic (noun)	Munda-Mon-Khmer (noun)
a family of languages spoken in southern and southeastern Asia	a family of languages spoken in southern and southeastern Asia