Now the ladies were on the side of Nicholas, and the gentlemen (being jealous) were on the side of the disappointed tragedian; so that the latter formed a little group about the redoubtable Mr Lenville, and the former looked on at a little distance in some trepidation and anxiety.
There are no more uses of "redoubtable" in the book.
Show samples from other sources
They remain, I suspect, a redoubtable seduction tool.
Khaled Hosseini -- And The Mountains Echoed
To the youth it was an onslaught of redoubtable dragons.