1. to make or become crisp; to make or become firm, dry, or brittle
2. to make or become lively, brisk, or sharp in manner or tone

Examples

• The cold air will crispen the lettuce leaves.
• She crispened her tone when addressing the late arrivals.
• The bacon crispened in the hot skillet.
• A brisk walk crispened his mood after a long day indoors.
• The autumn breeze crispened the morning air.
• He crispened the edges of the pastry before baking.