Re*dou"ble (r?*d?b"'l), v. t. [Pref. re- + double: cf. F. redoubler. Cf. Reduplicate.] 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.

Re*dou"ble, v. i. To become greatly or repeatedly increased; to be multiplied; to be greatly augmented; as, the noise redoubles.