Booties are shoes or slippers with coverage that extends beyond the foot to cover the ankle and possibly part of the leg.
About Slippers:
A type of shoe typically designed for indoor use that can be a variety of styles, including slides, mocassins, scuffs, booties, thongs, or loafers. Usually the uppers are made of soft leather or other fabrics (as opposed to tougher fabrics like hard leather that regular shoes are made of) and are sometimes lined with soft materials like felt, shearling or wool.