morale vs mental state

morale and mental state both are nouns.

Word	Noun	Adjective	Verb	Adverb
morale	Yes	No	No	No
mental state	Yes	No	No	No

As nouns, mental state is a hypernym of morale; that is, mental state is a word with a broader meaning than morale:

morale: a state of individual psychological well-being based upon a sense of confidence and usefulness and purpose
mental state: (psychology) a mental condition in which the qualities of a state are relatively constant even though the state itself may be dynamic

Other hypernyms of morale include mental condition, psychological condition, psychological state.

morale (noun)	mental state (noun)
the spirit of a group that makes the members want the group to succeed	(psychology) a mental condition in which the qualities of a state are relatively constant even though the state itself may be dynamic
a state of individual psychological well-being based upon a sense of confidence and usefulness and purpose