mudguard       
noun [ C ] mainly UK uk/ˈmʌd.ɡɑːd/ us/ˈmʌd.ɡɑːrd/ (US usually fender)
 (自行车或摩托车的)挡泥板
a curved piece of metal or plastic above the wheels of a bicycle or motorcycle that prevents dirt from getting on the rider
 Compare: mudflap splash guard 
See also: guard noun (DEVICE)