mix up vs muddle

mix up is not a noun while muddle is a noun.

Word	Noun	Adjective	Verb	Adverb
mix up	No	No	Yes	No
muddle	Yes	No	Yes	No

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

Other hyponyms of mix up include addle, puddle.

mix up (noun)	muddle (noun)
	a confused multitude of things
	informal terms for a difficult situation

mix up (verb)	muddle (verb)
cause to be perplexed or confounded	mix up or confuse
assemble without order or sense	make into a puddle