To whip; flog; spank; to beat s.t. against s.t. [-an].
The -an imp. focuses on the thing one is beating against s.t. as when s.o. is washing clothes and beats the clothes against s.t. The -un imp. focuses on the one being whipped or flogged.
I'll whip/spank you if you don't stop crying.
Beat your wash on s.t. so all the dirt will be removed.
That cow's tail whipped me in the face.