Cut looks like you are cutting something with a pair or scissors. Extend your index finger and middle finger to make the blades of the scissors (like a 'V' sign in ASL, only horizontally oriented with your hand facing your body), then close the fingers to make a cutting motion while moving your whole hand forward, or in front of your chest from right to left (if your right hand is dominant).
Usage: Cut is a useful sign for babies that like crafts. Because you may not want a pair of scissors lying around with a young child, you can keep the scissors out of reach - but teaching baby cut allows her to communicate when she wants you to get them out. Simple activities like cutting or painting will help baby develop her gross motor skills, while having fun (and making a mess).
Cut is a very versatile sign that will help convey a variety of concepts. Use it when crafting, cooking or if your child is injured.