Redouble /(r?*d?b"'l)/

Re·dou·ble

Redouble

v. t.
  1. To double again or repeatedly; to increase by continued or repeated additions; to augment greatly; to multiply.
    So they Doubly redoubled strokes upon the foe.

Redouble

v. i.
  1. To become greatly or repeatedly increased; to be multiplied; to be greatly augmented; as, the noise redoubles.