IPA: /ˈfɔːrmɪdəbl/
KK: /ˈfɔrmɪdəbl/
Causing fear or respect because of being very large, powerful, or difficult to deal with.
The team faced a formidable opponent in the championship game.
Formidable is derived from the Latin root "formidabilis" (meaning to be feared) which comes from "formidare" (meaning to fear). The suffix "-able" (meaning capable of) indicates that something is capable of inspiring fear. Thus, formidable describes something that is capable of causing fear or dread.
Think of something that is 'capable of causing fear' — that's what formidable means.