1) Challenge 2) Contest at law 3) Contest at the bar 4) Contest in a way 5) Engage in legal proceedings 6) File a suit against 7) Go to court 8) Go to law 9) Not settle 10) Take it to court 11) Take to court 12) To carry on a lawsuit 13) To contest in law 14) To go to law 1) Sue 
• (v. i.) To carry on a suit by judicial process. • (v. t.) To make the subject of a lawsuit; to contest in law; to prosecute or defend by pleadings, exhibition of evidence, and judicial debate in a court; as, to litigate a cause.
Lit'i·gate intransitive verb To carry on a suit by judicial process. Lit'i·gate transitive verb [ imperfect & past participle Litigated ; present participle & verbal noun Litigating .] [ See Litigation .] To make the subject of a lawsuit; to contest in law; to prosecute or defend by pleadings, exhib...
[v] - engage in legal proceedings
litigate 1. To engage in legal proceedings. 2. To institute legal proceedings against; to file a suit against.