信しん義ぎ則そくしんぎそくMeanings1nounprinciple of good faith and fairnesslaw›Legal principle requiring parties to act honestly and fairly, often invoked in contract law. Abbreviation of 信義誠実の原則.See also: 信義誠実の原則契けい約やくの解かい釈しゃくには信しん義