不ふ信しん実じつMeanings1nouninsincerity; unfaithfulnessRefers to a lack of sincerity or faithfulness in character or actions. Often used in formal or literary contexts.彼かれの不ふ信しん実じつな態たい度どに失しつ望ぼうした。I was disappointed by his insincere attitude.不ふ信しん実じつは人にん間げん関かん係けいを壊こわす。Insincerity destroys human relationships.