dreaded vs frightening

dreaded is not a noun while frightening is a noun.

Word	Noun	Adjective	Verb	Adverb
dreaded	No	Yes	No	No
frightening	Yes	Yes	No	No

As adjectives, dreaded and frightening are synonyms defined as:

Other synonyms of dreaded include awful, dire, direful, dread, dreadful, fearful, fearsome, horrendous, horrific, terrible.

dreaded (noun)	frightening (noun)
	the act of inspiring with fear

dreaded (adjective)	frightening (adjective)
causing fear or dread or terror	causing fear or dread or terror