morning vs early-morning hour

morning and early-morning hour both are nouns.

Word	Noun	Adjective	Verb	Adverb
morning	Yes	No	No	No
early-morning hour	Yes	No	No	No

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