Learn the meaning of formidable , an adjective that describes something or someone that inspires fear, dread, or admiration. Find synonyms, pronunciation, word origin, and usage examples from Collins Dictionary. Meaning The term ‘ formidable ’ describes something or someone that is powerful, impressive, or worthy of respect, and often instills a sense of fear or awe. FORMIDABLE definition : 1. Someone who is formidable is strong and slightly frightening: 2. difficult and needing a lot of…. Learn more. Formidable definition : causing fear, apprehension, or dread.. See examples of FORMIDABLE used in a sentence.