Inimitable (adjective)

1. Impossible to imitate or match in quality or style.
2. Impossible to equal or surpass.

Origin:

From latin inimitabilis (unmatched, incomparable), from in- (not) + imitari (to imitate).

Examples:

1. His writing style was inimitable.
2. Her singing voice was inimitable.
3. His sense of humor was inimitable.
4. His performance was inimitable and unforgettable.
5. His art was inimitable, no one could match his technique.