Form "O" hands and hold them out in front of you palms facing mostly toward each other and a little bit forward. Then quickly move your hands forward and shake your head "no" once.
This sign can also be done with one hand.
As I'm doing it here, the sign is almost identical to a casual version of
Also see: "NOTHING" so you can check out the signs "hear-nothing" and "know-nothing."
American Sign Language University ™ ASL resources by Lifeprint.com © Dr. William Vicars