brandir

To brandish or wave something aloft, often as a threat, a show of force, or a triumphant gesture (brandir une arme, brandir un drapeau, brandir un document comme preuve). Common in journalism and narrative writing.

• Le manifestant brandissait une pancarte. — The protester was brandishing a sign.
• Elle a brandi son diplôme fièrement. — She proudly held up her diploma.
• Il brandit la menace d'un procès. — He's brandishing the threat of a lawsuit.

Brandir implies holding something up visibly and often assertively — for simply holding an object (no display or threat implied), tenir is the neutral verb; brandir always adds that dramatic, showing-off quality.