Renowned

The most appropriate antonym of the word renowned is unknown.

• Renowned means "having a great reputation or fame."
• Unknown means "not known or familiar."

The other words do not have the same meaning as "renowned" and are therefore not antonyms.

• Celebrated means "widely known and admired."
• Unlucky means "having bad luck or misfortune."
• Superior means "of higher quality, standard, or grade."