In Ray Kurzweil's book, The Age of Spiritual Machines, MOSH is an acronym
for "Mostly Original Substrate Humans."
In the book, Kurzweil theorizes about the rise of advanced computer
technology and artificial intelligence. He foresees that in the future,
the line between machines and humans will become indistinguishable, and that
most humans will be enhanced by neural implants. A MOSH is someone who does
not have any enhancements, which according to Kurzweil will be unusual by
2099.