WordWeb Online

1. Violent and sudden and noisy
   "a slam-bang collision"

1. In a careless or reckless manner
   "the shelves were put up slam-bang";
   - slapdash
    
2. With heedless speed
    
3. In a violent, sudden or noisy manner
   "the pans fell slam-bang and woke the whole house";
   - slap-bang [informal]

See also: violent