Such is a predicate adjective (also referred to more generally as a subject complement). It modifies Sorrow, which is the subject of this sentence. The order of this sentence is inverted from the typical English, which would be " Her sorrow is such." Therefore, sorrow in this case is an adjective because it modifies a noun.
The word 'such' is an adverb.
adverb
what part of speech is work
i want to know what part of speech is camping
what part of speech is beneath
what part of speech is eleven
The part of speech for "answer" is a noun.
part of speech
The part of speech for this particular word is a noun.
what part of speech is beneath
what part of speech is work
adverb
The part of speech for "explicit" is an adjective.
The part of speech for "indefinite" is an adjective.
The part of speech for "unfamiliar" is an adjective.
The part of speech for "twirl" is a verb.
The part of speech of "came" is a verb.
The part of speech for "buried" is a verb.