or napper , a hat. From “nab,” a hat, cap, or head.—Old Cant.
To nap: To cheat at dice by securing one chance. Also to catch the venereal disease. You've napt it; you are infected.
sb. cupVariants: neppe, dat.Etymology: Anglo-Saxon hnæp ; cp. Old High German hnapf Old French hanap (Bartsch)Low Latin nappus
to break, or rap with a hammer. See knap.—North.
or nab , to take, steal, or receive; “you'll nap  it,” i.e., you will catch a beating.—North ; also Old Cant.