yell vs shout out

yell is a noun but shout out is not a noun.

Word	Noun	Adjective	Verb	Adverb
yell	Yes	No	Yes	No
shout out	No	No	Yes	No

As verbs, yell and shout out are synonyms defined as:

Other synonyms of yell include call, cry, holler, hollo, scream, shout, squall.

yell (noun)	shout out (noun)
a loud utterance; often in protest or opposition
a loud utterance of emotion (especially when inarticulate)

yell (verb)	shout out (verb)
utter or declare in a very loud voice	utter a sudden loud cry
utter a sudden loud cry	utter in a very loud voice