The affliction upon the rear of the forearm from repeatedly missing a swing during a game of conkers and hitting your arm. The pain for the next couple of days is known as conker-arm.
Boss: James you have been off work for the past 3 days, why?
James: Conker-arm
Boss: A worthy cause.
James: Conker-arm
Boss: A worthy cause.
by The Wicks September 27, 2006