horrendous vs dreadful

horrendous and dreadful both are adjectives.

Word	Noun	Adjective	Verb	Adverb
horrendous	No	Yes	No	No
dreadful	No	Yes	No	No

As adjectives, horrendous and dreadful are synonyms defined as:

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

horrendous (adjective)	dreadful (adjective)
causing fear or dread or terror	causing fear or dread or terror
	exceptionally bad or displeasing
	extremely disagreeable and unpleasant