Gash/ɡæʃ/ Definition 1 of 3Pro Tip 1/3Severity of Injury Indicates a serious injury, more severe than a scratch or nick. The accident left a nasty gash on his leg. Pro Tip 2/3Visualization Imagine a deep, open cut to grasp the severity suggested by 'gash'. The gash was so deep you could see the bone. Pro Tip 3/3Medical Attention Often requires professional medical treatment, like stitches. That gash on your arm looks bad; you should see a doctor.