fearsome
Word family (noun) fear fearfulness ≠ fearlessness (adjective) fearful ≠ fearless fearsome (verb) fear (adverb) fearfully ≠ fearlessly
From Longman Dictionary of Contemporary Englishfearsomefear‧some /ˈfɪəsəm $ ˈfɪr-/ adjective FRIGHTENEDvery frightening a fearsome weaponExamples from the Corpusfearsome• Great big and fearsome Dimetrodon, a species of dinosaur, was the most powerful creature.• There was the other, fearsome, face of royalty.• They watched him intently, like a group of schoolboys would a fearsome master.• He would be a fearsome opponent.