grieving vs bereaved

grieving is not a noun while bereaved is a noun.

Word	Noun	Adjective	Verb	Adverb
grieving	No	Yes	No	No
bereaved	Yes	Yes	No	No

As adjectives, grieving and bereaved are synonyms defined as:

Other synonyms of grieving include bereft, grief-stricken, mourning, sorrowing.

grieving (noun)	bereaved (noun)
	a person who has suffered the death of someone they loved

grieving (adjective)	bereaved (adjective)
sorrowful through loss or deprivation	sorrowful through loss or deprivation