formidable
FOR-mih-duh-buladjMeaning inspiring fear or respect through size, strength or difficulty
Memory hook FORM-idable: a FORM so big you fear it. The dragon guarding the gate is huge, fast and clever, and even brave Maya takes a deep breath: it is a formidable foe.
The chess champion was a formidable opponent.
In context With its steep walls, deep moat and towering gate, the castle presented a formidable obstacle to anyone hoping to get inside.
Similar daunting, intimidating, imposing, powerful
Opposite weak, feeble, unimpressive
From Latin formidabilis, from formidare (to fear), from formido (fear).