louse

1 plural liceplay \ˈlīs\ a :  any of various small wingless usually flattened insects (orders Anoplura and Mallophaga) parasitic (see parasite 2) on warm-blooded animalsb :  a small usually sluggish arthropod (such as a biting louse) that lives on other animals or on plants and sucks their blood or juicesc :  any of several small arthropods (such as a book louse) that are not parasitic

2 plural lousesplay \ˈlau̇-səz\ :  a contemptible person :  heel what a beast, what a cad, what a louse he had been — Walter Karig