Any of numerous small,flat-bodied,wingless biting or sucking insects of the orders Mallophaga or Anoplura,many of which are external parasites on various animals,including human beings.

• 虱，寄生虫无数小的，身体扁平，没翼的咬人吸血昆虫，其中许多是多种动物的外部寄生物。