white lie
From Longman Dictionary of Contemporary Englishwhite lieˌwhite ˈlie noun [countable] informal LIE/TELL A LIEa lie that you tell someone in order to protect them or avoid hurting their feelingsExamples from the Corpuswhite lie• What's the harm of a white lie if it will make her feel better?• Why hadn't she told a white lie and claimed she had a licence?• What did it matter, a little white lie like that?