disappointment vs dashing hopes

disappointment and dashing hopes both are nouns.

Word	Noun	Adjective	Verb	Adverb
disappointment	Yes	No	No	No
dashing hopes	Yes	No	No	No

As nouns, disappointment and dashing hopes are synonyms defined as:

disappointment and dashing hopes: an act (or failure to act) that disappoints someone

disappointment (noun)	dashing hopes (noun)
an act (or failure to act) that disappoints someone	an act (or failure to act) that disappoints someone
a feeling of dissatisfaction that results when your expectations are not realized