Capable of being feared; something that can inspire fear or dread in others.
From 'fear' plus the productive suffix '-able,' which means 'capable of being' or 'worthy of.' This is a constructed adjective following standard English word-formation rules.
While grammatically correct, 'fearable' almost never appears in print because 'fearsome' and 'terrible' do the job so much better—it's a word that English's own morphological system allows but collective usage has rejected.
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