Dampen (verb)

1. To make something less intense or lively.
2. To make something less enthusiastic or eager.
3. To make something less dry by adding moisture.

Origin:

From middle english dampen, from old english dampian; akin to old high german dampf damp.

Examples:

1. The rain dampened the fireworks display.
2. The bad news dampened their spirits.
3. He dampened the cloth before wiping the dust off the table.
4. The criticism dampened her enthusiasm for the project.
5. The heat wave has dampened the sales of ice cream.