1. a substance or agent that makes something darker in color or shade
Usage: commonly used in cosmetics, art, and manufacturing contexts
2. a person or thing that darkens or causes darkness
Usage: less common; often used figuratively

Examples

• She applied an eyebrow darkener to enhance her features.
• The artist used a darkener to deepen the shadows in the painting.
• This hair darkener is formulated to be gentle on sensitive scalps.
• The storm clouds acted as a natural darkener, blocking out the sun.
• Chemical darkeners are often used in leather tanning.
• The darkener in the wood stain gave the furniture a richer appearance.