From Longman Dictionary of Contemporary Englishdreadfuldread‧ful /ˈdredfəl/ ●●○ adjective 1 UNPLEASANTextremely unpleasant SYN terrible We’ve had some dreadful weather lately. Michelle felt absolutely dreadful (=very ill).► see thesaurus at bad, horrible2 [only before noun]BAD used to emphasize how bad something or someone is SYN terrible a dreadful mistakeGrammarDreadful is not used with ‘very’. You say: The food was absolutely dreadful. ✗Don’t say: The food was very dreadful.
Examples from the Corpusdreadful• "How did you like the film?'' "I thought it was dreadful.''• The coffee tasted dreadful!• Sleazy and tedious, the film would need to improve a few rungs to be classified as merely dreadful.• The Reformers might be followers of Erasmus; but they had no hesitation in drowning the dreadful Anabaptists.• And in any case, what Lucy may have done was surely not so dreadful and will be soon forgotten.• In a medical centre they found dreadful cases of malnutrition, scabies and diarrhoea.• Then she had the dreadful feeling that he was not going to answer her anyway, for he said nothing.• The doctor wouldn't allow sedatives, or painkillers when he had those dreadful headaches.• Young made two dreadful mistakes.• Ah, it's dreadful, sometimes.