mourning vs manifestation

mourning and manifestation both are nouns.

Word	Noun	Adjective	Verb	Adverb
mourning	Yes	Yes	No	No
manifestation	Yes	No	No	No

As nouns, manifestation is a hypernym of mourning; that is, manifestation is a word with a broader meaning than mourning:

Other hypernyms of mourning include activity, expression, reflection, reflexion.

mourning (noun)	manifestation (noun)
the passionate and demonstrative activity of expressing grief	a public display of group feelings (usually of a political nature)
state of sorrow over the death or departure of a loved one	a manifest indication of the existence or presence or nature of some person or thing
	expression without words
	a clear appearance
	an appearance in bodily form (as of a disembodied spirit)

mourning (adjective)	manifestation (adjective)
sorrowful through loss or deprivation