formidable

FOR-muh-duh-buhl

meaning in plain English

Very big, strong, or powerful, so it makes people feel scared or impressed.

Imagine a huge, scary guard—so big and strong he's downright formidable.

for example

The mountain looked formidable, and the climbers hesitated before trying to reach the summit.

Think of a huge, snarling dog that blocks your path—its size and strength make it a formidable obstacle. You might feel a mix of fear and awe because it seems hard to get past.