欣快（英语：Euphoria ，英语发音：/juːˈfɔəriə/，来源于古希腊语 εὐφορία）（词义与烦躁相反），在医学上把它当做一种精神和情感的状态。心情愉快、无忧无虑、兴高采烈、异常幸福、兴奋、喜悦。从技术上来说，欣快在心理学中属于行为，但该术语通常俗称用来形容一种对事物超然的幸福和具有压倒性的知足感的一种情绪波动。它也被定义为“情感状态呈现出夸张的幸福或兴高采烈”。这个英语词源于希腊语的εὐφορία，“轻松、持久的力量”。

欣快感被普遍认为是一种病态的身体和心理状态，有时会通过使用精神药品来达到，而不是通过正常方式得到一种人类中的精神状态。然而，一些自然的行为，如性高潮，爱，或取得比赛胜利的运动员，可诱发短暂的这种兴奋状态。

Euphoria (pronunciation: /juːˈfɔəriə/) is an affective state and a form of pleasure in which a person experiences intense feelings of well-being, happiness, and excitement. Certain drugs, many of which are addictive, are known to cause euphoria. Similarly, certain natural rewards and social activities, such as physical exercise, laughter, music-making, and dancing, can induce a state of euphoria. Euphoria has also been cited as being experienced by those participating in certain religious or spiritual rituals and meditation. Euphoria is also known to occur as a symptom of mania.