formidable

The small team faced a formidable opponent who hadn't lost a single game all season.

(Chinese) 这支小球队面对的是一个在本赛季一场未输的强大对手。

Climbing Mount Everest remains a formidable challenge even for experienced mountaineers.

(Chinese) 即使对于经验丰富的登山者来说，攀登珠穆朗玛峰仍然是一项极其艰巨的挑战。