fling (one's) arms up(redirected from fling their arms up)
fling (one's) arms up
To toss or jerk one's arms upward, typically to convey some emotion. As the kids ran around the room shrieking, Mom just flung her arms up and shook her head. I can't hear what they're saying, but it looks like Dad just flung his arms up in anger, so that's not a good sign.