Source : Webster's Revised Unabridged Dictionary (1913)

Slam-bang \Slam"-bang`\, adv.
   With great violence; with a slamming or banging noise.
   [Colloq.]

Source : WordNet®

slam-bang
     adj : violent and sudden and noisy; "a slam-bang collision"
     adv 1: in a careless or reckless manner; "the shelves were put up
            slapdash" [syn: {slapdash}]
     2: with heedless speed; "yachts ran slap-bang into the convoy
        at 15 knots an hour"
     3: in a violent or sudden or noisy manner; "the pans fell
        slam-bang and woke the whole house" [syn: {slap-bang}]