noun, na-adjective
neglect of social obligations; dishonorable conduct
Refers to failing to fulfill expected social duties, such as not returning favors, not attending important events, or acting ungratefully. Often implies a breach of 義理 (social/moral obligation).
お世話になった人に挨拶もせずに引っ越すのは不義理だ。
Moving away without even greeting the people who helped you is a neglect of social obligations.
彼は不義理な態度で周囲の信頼を失った。
He lost the trust of those around him through his dishonorable attitude.
noun, na-adjective
failure to repay a debt
Specifically refers to not repaying borrowed money or a financial obligation, seen as a serious breach of trust.
借金を返さないのは不義理だ。
Not repaying a debt is a failure to meet one's obligations.
不誠実 means insincere or dishonest in a general sense, while 不義理 specifically relates to failing social or financial obligations.
Compound of 不 (fu-, 'not') + 義理 (giri, 'social obligation, duty'). The reading ふぎり is a standard on'yomi combination.