Named after John Neper - Scottish mathematician (1550-1617).
Neper is an old lunar impact crater located near the eastern limb. Due to its location the crater must be viewed during a suitable libration, and is very foreshortened. The crater lies on the south edge of Mare Marginis, to the east of the crater Jansky. To the northwest across the Mare Marginis is the crater Goddard. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On the Moon they are named after deceased scientists, polar explorers, astronauts or cosmonauts.