mar (v.) Look up mar at Dictionary.com
Old English merran (Anglian), mierran (West Saxon) "to waste, spoil," from Proto-Germanic *marzjan (source also of Old Frisian meria, Old High German marren "to hinder, obstruct," Gothic marzjan "to hinder, offend"), from PIE root *mers- "to trouble, confuse" (source also of Sanskrit mrsyate "forgets, neglects," Lithuanian mirszati "to forget"). Related: Marred; marring.