dampen

Etymology

From damp + -en.

verb

1. (transitive) To make damp or moist; to make moderately wet.
2. (intransitive) To become damp or moist.
3. (transitive) 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.
   He was dreadfully familiar with everything, and talked about some places we were longing to see in a way that considerably dampened our enthusiasm. 1883 "Pomona's Daughter", Frank R. Stockton, in The Century, vol. XXVI, number 1, May, page 25
   Pregnant women are 20 times as likely as other healthy young women to contract listeriosis, probably because in pregnancy the immune system is dampened to prevent rejection of the fetus. October 16 2007, Jane E. Brody, “Despite Strides, Listeria Needs Vigilance”, in The New York Times
   The firm said changes in consumer behaviour had also dampened demand for the powder. 2020-05-20, “J&J to sell baby powder in UK despite stopping US sales”, in BBC, London: BBC, retrieved 2020-05-22
4. (intransitive) To become damped or deadened.