skeleton vs skeleton in the closet

skeleton and skeleton in the closet both are nouns.

Word	Noun	Adjective	Verb	Adverb
skeleton	Yes	No	No	No
skeleton in the closet	Yes	No	No	No

As nouns, skeleton and skeleton in the closet are synonyms defined as:

Other synonyms of skeleton include skeleton in the cupboard.

skeleton (noun)	skeleton in the closet (noun)
the internal supporting structure that gives an artifact its shape	a scandal that is kept secret
the hard structure (bones and cartilages) that provides a frame for the body of an animal
a scandal that is kept secret
something reduced to its minimal form