fear ‧ some /ˈfɪəs ə m $ ˈfɪr-/ BrE AmE adjective
[ Word Family: noun : ↑ fear , ↑ fearfulness ≠ ↑ fearlessness ; adjective : ↑ fearful ≠ ↑ fearless , ↑ fearsome ; verb : ↑ fear ; adverb : ↑ fearfully ≠ ↑ fearlessly ]
very frightening:
a fearsome weapon