1. not worthy of honor; bringing shame or disgrace
Usage: British spelling; American spelling is 'dishonorable'
2. involving or characterized by a lack of integrity or moral principles
Usage: often used to describe conduct or behavior

Examples

• His dishonourable conduct during the scandal damaged his reputation permanently.
• The athlete was banned for dishonourable behavior on the field.
• It would be dishonourable to break a promise made to a friend.
• The general's dishonourable retreat left his troops vulnerable.
• She refused to engage in the dishonourable scheme her colleagues proposed.
• Cheating on the exam was considered dishonourable by the school community.