(transitive) To double, especially to double again; to increase considerably; to multiply; to intensify.Having lost sight of our objectives, we redoubled our efforts.
1846, Herman Melville, Typee, ch. 10:Every item of intelligence appeared to redouble the astonishment of the islanders, and they gazed at us with inquiring looks.
1903, "Plunder Hidden in Graves," New York Times, 21 Oct., p. 16:The police redoubled their efforts to capture the thieves.
(bridge, backgammon) To double an opponent's doubling bid.