"nothing at all," 1968, U.S. slang, from jack (n.) + shit (n.).
jack-knife
Jack-o'-lantern
jackpot
jack-rabbit
jacks
jack-shit
Jacksonian
jackstraw
Jacob
Jacobean
Jacobin
)window.location='https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=byronic106@yahoo.com&lc=US&item_name=Donation+to +Help+Keep+Etymonline+Free+and+Open&no_note=0&cn=&curency_code=USD&bn=PP-DonationsBF:btn_donateCC_LG.gif:NonHosted'){kind=link}