tort·fea·sor 
(tôrtfē′zər)
(tôrtfē′zər)n.
One that commits a tort.
[Middle French tortfaiseur, wrongdoer : tort, wrong, injury (from Old French; see TORT) + faiseur, doer (from Old French : faire, fais-, to do; see FEASIBLE + -eur, -er, -or; see -OR1).]