Clearheaded (adjective)

1. Having a clear and rational mind; not confused or muddled.
2. Characterized by good judgement and the ability to think clearly under pressure.

Origin:

From the phrase clear + headed, meaning having a clear mind or good judgement.

Examples:

1. She remained calm and clearheaded during the crisis.
2. He was clearheaded even after a long night of partying.
3. The clearheaded decision of the manager saved the company from financial ruin.
4. It is important to remain clearheaded when making important decisions.
5. She is a clearheaded leader who always acts in the best interest of her team.