To attempt to block or hinder someone else's success in your field/industry though backroom dealings and other means of influence. These attempts are generally done by someone who perceives you as a threat. Often, these attempts are obvious and make the genshafter look desperate to maintain the status quo.
Named after Judy Genshaft, the president of the University of South Florida, who continues to try and block the University of Central Florida, another nearby state school on the rise, from entering the same NCAA conference as USF as not to weaken her institution.
"By blocking UCF from procuring big-time BCS money to fund its athletic program, USF is "Genshafting" the State of Florida out of millions of dollars." -Mike Bianchi, Orlando Sentinel