1. To behave or run around in a wild, unruly, out-of-control manner; to be or become crazy or chaotic. We tried to have some organized games for the kids, but they all started running amuck as soon as they got here. The villagers were cleaning up debris for days after the bulls ran amuck through the streets.

2. To become bad or go awry; to get out of control; to go haywire. This whole operation has run amuck. I don't know how we can be expected to finish under the deadline in these conditions.

3. dated To rush around in a violent, murderous frenzy. (Note: This is the phrase's original specific meaning, taken from Malay. "Amuck" is an older alternative spelling of "amok," which is preferred today.) Fueled by alcohol and cocaine, Dave ran amuck when his wife told him she'd been seeing someone else. Luckily, a neighbor called the police when they heard such a commotion.