She expertly played the piano.

She expertises in computer programming.

She has many expertises in various fields.

He is the expertest person in the field.

He is an expertocratic leader.

The expertocrats gathered to discuss the future of the industry.

He is considered an expertocrat in the field of economics.

Expertocracies are systems of government where decision-making power is held by experts.

Expertocracy is a system of government where experts rule.

She has acquired many expertships in her field.