Literally, Nolo contendere is for Latin for "I do not wish to contend." In the American judicial system, this is most commonly known as entering a plea of "No Contest".
A defendant in a criminal proceeding may enter a plea of nolo contendere ("no contest") which allows the defendant to neither admit guilt or deny responsibility for the crimes in which they are charged, but still accepts any punishment the court may impose. This would be submitted in lieu of entering a plea of either Guilty or Not Guilty.