good morning vs morning

good morning and morning both are nouns.

Word	Noun	Adjective	Verb	Adverb
good morning	Yes	No	No	No
morning	Yes	No	No	No

As nouns, good morning and morning are synonyms defined as:

good morning and morning: a conventional expression of greeting or farewell, used to wish someone a good morning

good morning (noun)	morning (noun)
a conventional expression of greeting or farewell, used to wish someone a good morning	a conventional expression of greeting or farewell, used to wish someone a good morning
	the earliest period
	the time period between dawn and noon
	the first light of day