knock-for-knock

adjective
  1. designating an agreement between vehicle insurers that in the event of an accident each will pay for the damage to the vehicle insured with him without attempting to establish blame for the accident
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012