HORRENDOUS Meaning of HORRENDOUS in English [ hɒ'rɛndəs ]■ adjective extremely unpleasant or horrifying.Derivatives~ly adverb OriginC17: from L. horrendus (gerundive of horrere (see horrid )) + -ous . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004