dampen

verb5

1. •
   To make damp or moist; to make moderately wet.
2. •
   To lessen; to dull; to make less intense (said of emotions and non-physical things).

   • We won't let the bad news dampen our spirits.
3. •
   To become damped or deadened.
4. •
   (nonstandard) To suppress vibrations (mechanical) or oscillations (electrical) by converting energy to heat (or some other form of energy).
5. •
   To become damp or moist.