1. An action or process that violates the law or established legal rules and regulations
The court ruled that the arrest was based on an illegal procedure.
O tribunal decidiu que a prisão foi baseada em um procedimento ilegal.
2. In sports or games, a violation of the rules that constitutes a breach of conduct
The referee called an illegal procedure penalty on the offensive line.
O árbitro marcou uma penalidade por procedimento ilegal na linha ofensiva.
3. Medical or surgical action performed without proper authorization or consent
The medical board investigated the doctor for performing an illegal procedure.
A junta médica investigou o médico por realizar um procedimento ilegal.