(chiefly US) A fictional pastime wherein a person sneaks up on a sleeping cow and pushes it over.
2005, Duke Rightious, The Official Cow Tipper's Handbook - [1] - "The medieval cow tippers were a rutheless lot, to be sure, with their Knights of the Round Bovine Topplers, and Cowalot...But times changed and so did the fashion and style of cow tipping."
2006, Jeremy Smith, Bum Bags and Fanny Packs: A British-American American-British Dictionary - [2] - "cow tipping v: a high school or college prank of sneaking up to a standing sleeping cow and pushing her over..."
2005, Michael D. Bauer, Linux Server Security - [3] - "If setting up your database server feels like as much work as raising cattle, but with-out the glamor, you may mix business with pleasure and perform some virtual cow tipping: sneak up on your database server and try to push it over."