Neoism comes and goes with every revolt against a previous -ism or art movement. However, the word first appeared in Canada in the mid- to late 1970s.

To sum Neoism up, it mostly defines itself by what it is not rather than what it is. The insistence of being an underground philosophy is a big part of its make up.

The whole idea is to avoid any historical categorisation. The artists effectively achieve this with a box of tricks. E.g they might share artist pseudonyms and identities, fake other artists, create contradicting definitions of themselves, and engage in pranks to mock the established art world.

You can read more about art movements here.