litigious (adj.) Look up litigious at Dictionary.com
"fond of engaging in lawsuits," 1620s, from Middle French litigieux and directly from Latin litigiosus "contentious, quarrelsome," from litigium "dispute, strife," from litigare "to dispute, quarrel; sue, go to court" (see litigation). The word was in Middle English with a now-obsolete sense "fond of disputes" (late 14c.), making it senior in English to litigate or litigation. Related: Litigiousness; litigiosity.