Buzzkill

Origin

The phrase "buzzkill" is a relatively modern American English colloquialism, bubbling up from the vibrant slang of the mid-20th century. It cleverly merges two distinct ideas: "buzz," which by the 1930s had already come to signify a feeling of exhilaration, excitement, or a pleasant high—whether from good company or a literal intoxicant—and "kill," meaning to stop or destroy. Thus, to "kill the buzz" was to extinguish that good feeling, that moment of elation. This evocative action of deflating a good mood or moment eventually became personified, with the agent or thing causing this deflation being dubbed a "buzzkill." It’s a direct, punchy term that immediately conveys the act of ruining someone's fun.