1. A process or method that does not follow established rules, standards, or legal protocols
The audit revealed an irregular procedure in the company's accounting practices.
A auditoria revelou um procedimento irregular nas práticas contábeis da empresa.
2. An official action taken in violation of customary or statutory procedures
The court ruled that the arrest was made through an irregular procedure.
O tribunal decidiu que a prisão foi efetuada através de um procedimento irregular.