Adjective redoubtable has 2 senses
- formidable, redoubtable, unnerving - inspiring fear; "the formidable prospect of major surgery"; "a tougher and more redoubtable adversary than the heel-clicking, jackbooted fanatic"- G.H.Johnston; "something unnerving and prisonlike about high gray wall"
Antonym: unalarming (indirect, via alarming)
- glorious, illustrious, redoubtable, respected - having or worthy of pride; "redoubtable scholar of the Renaissance"; "born of a redoubtable family"
Antonym: humble (indirect, via proud)
,