To gouge can mean to make a hole or dent in something, or to swindle or steal by overcharging. If your local gas station raises prices because a storm is coming, you may say that the station owner is gouging you — and that's illegal.
The verb gouge means to cut or carve. You can use special chisels to gouge linoleum for interesting design in printing. As a noun, a gouge is the tool you would use — instead of a flat-head chisel, a gouge has a trough — to make the gouge marks of the design. Another meaning of the verb gouge is an indentation in the surface of something. If you're not careful with the screwdriver, you'll accidentally gouge a hole in the wall.