A plaintiff is the party who initiates a lawsuit before a court. By doing so, the plaintiff seeks a legal remedy. If this search is successful, the court will issue judgment in favor of the plaintiff and make the appropriate court order. "Plaintiff" is the term used in civil cases in most English-speaking jurisdictions, the notable exceptions being England and Wales, where a plaintiff has, since the introduction of the Civil Procedure Rules in 1999, been known as a "claimant" and Scotland, where the party has always been known as the "pursuer". In criminal cases, the prosecutor brings the case against the defendant, but the key complaining party is often called the "complainant".

ନ୍ୟାୟଶାସ୍ତ୍ର ଅନୁସାରେ ସାଧାରଣତଃ ପ୍ରଥମ ପକ୍ଷ, ଅପର ପକ୍ଷ ବିରୁଦ୍ଧରେ କୌଣସି ଅଭିଯୋଗ ନେଇ ଅଦାଲତର ଦ୍ୱାରସ୍ଥ ହୁଅନ୍ତି । ଭାରତର ନ୍ୟାୟୀକ ବ୍ୟବସ୍ଥାରେ ବିଶେଷଭାବେ ଦେୱାନୀ ମକଦ୍ଦମାରେ ଏହି ପ୍ରଥମ ପକ୍ଷକୁ ବାଦୀ କୁହାଯାଏ । ଅଭିଯୋଗର ସାମନା କରୁଥିବା ଦ୍ୱିତୀୟ ପକ୍ଷକୁ ପ୍ରତିବାଦୀ କୁହାଯାଏ ।