dreadful vs horrendous

dreadful and horrendous both are adjectives.

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

As adjectives, dreadful and horrendous are synonyms defined as:

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

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