Formidable (adjective)

1. Inspiring fear or respect through being impressively large, powerful, intense, or capable.
2. Arousing admiration and respect through being impressively large, powerful, intense, or capable.
3. Causing fear or respect through being impressively difficult.
4. Difficult to defeat, overcome, or deal with.

Origin:

From french formidable, from forme ("shape, form") + -able (from latin -abilis)..

Examples:

1. Mount Everest is a formidable challenge for climbers.
2. The test was formidable, it required a lot of hard work and dedication.
3. He faced a formidable opponent in the tournament.
4. She is a formidable politician and one of the most powerful women in the country.
5. The company has a formidable reputation in the industry.