To dampen something such as someone's enthusiasm or excitement means to make it less lively or intense.
例句
Nothing seems to dampen his perpetual enthusiasm...似乎沒有什么能讓他那持久的熱情消退。I hate to dampen your spirits but aren't you overlooking a couple of minor points.我不想掃你的興，但你是否忽視了幾個小的問題呢？
VERB
使潮濕;弄濕
If you dampen something, you make it slightly wet.
例句
She took the time to dampen a washcloth and do her face.她花了點時間弄濕毛巾，洗了把臉。