1. to make something acceptable or valid according to law or established rules
Usage: British spelling; American spelling is ‘legitimize’
2. to give official recognition or approval to something
Usage: British spelling

Examples

• The new government sought to legitimise its authority through democratic elections.
• The university decided to legitimise the student organization by granting it official status.
• Critics argued that the policy would legitimise discrimination.
• The treaty helped legitimise the country’s territorial claims.
• She worked to legitimise alternative medicine practices through scientific research.
• The court ruling served to legitimise the company’s business practices.