pit [OE] The pit that is a large hole in the ground is based on Latin puteus ‘well shaft’. As a North American term for the stone of a fruit, pit seems to have been taken from Dutch in the 19th century, and is related to Old English pith. Since the 1960s people have used pits as an informal shortened term for armpits [ME]. These often have a tendency to be damp and smelly and so it was but a small linguistic leap to have them symbolize the worst example of something. That is one explanation of to be the pits, ‘to be extremely bad’. The verb meaning ‘to test in a conflict or competition’, as in pit your wits, comes from the former practice of setting animals such as cocks or dogs to fight each other. The creatures were ‘pitted’ or put together in a pit or other enclosure (literally a *cockpit), a sense used from the mid 18th century.