mood vs grammatical relation

mood and grammatical relation both are nouns.

Word	Noun	Adjective	Verb	Adverb
mood	Yes	No	No	No
grammatical relation	Yes	No	No	No

As nouns, grammatical relation is a hypernym of mood; that is, grammatical relation is a word with a broader meaning than mood:

mood: verb inflections that express how the action or state is conceived by the speaker
grammatical relation: a linguistic relation established by grammar

mood (noun)	grammatical relation (noun)
a characteristic (habitual or relatively temporary) state of feeling	a linguistic relation established by grammar
verb inflections that express how the action or state is conceived by the speaker
the prevailing psychological state