WordWeb Online

1. Become much greater in intensity or size or amount
   "we faced redoubled attacks from the enemy"; "despite our redoubled efforts"

1. Double in magnitude, extent, or intensity
   "The enemy redoubled their screaming on the radio"
    
2. Double again
   "The noise doubled and redoubled"
    
3. Make twice as great or intense
   "The screaming redoubled"

See also: increased

Type of: deepen, double, duplicate, escalate, intensify, step up