mudguard

A shield over or behind a vehicle’s wheel to prevent mud or water from splashing onto that vehicle or a following vehicle.

A strip of leather, rubber, or other material added to the upper of a shoe just above the sole as protection against mud and water or as a decoration.

a cover over the wheels of a vehicle, or a flap behind that wheel, to prevent water and mud being projected.

a curved piece above the wheel of a bicycle or motorcycle to protect the rider from water or mud thrown up by the wheels