1. relating to punishment or penalties, especially those imposed by law
2. relating to or used for the confinement of criminals

Examples

• The judge imposed the maximum penal sentence allowed by law.
• Penal reform advocates argue for rehabilitation over punishment.
• The penal code was updated to include new cybercrime offenses.
• He was sent to a penal institution for five years.
• The penal system focuses on deterring future crimes.
• Penal colonies were once used to house convicted criminals.
• The lawyer studied penal law to better defend his clients.