The phrase mukatsuku in Japanese means to get angry, and gained currency in the 1980s, originating in the Kansai dialect of Japan. Mukatsuku gained particular notoriety as an expression of dissatisfied youth when it was used in 1998 by the 13-year-old junior high school student who stabbed one of his teachers to death at his school in Tochigi prefecture because her reprimand for his being late for class made him mukatsuku.
The origin of the Japanese word mukatsuku is the onomatopoeia muka-muka which describes the feeling of acid reflux or heartburn. Although mukatsuku has the ring of adolescent slang from no more than three decades ago in Japan, the word itself actually dates back several centuries, probably to the Heian era at the latest. Extant medical texts from that time apparently contain the phrases muka-muka and mukatsukamu in the context of an upset stomach and nausea.
Another phrase referring to the stomach is “hara ga tatsu” (literally “the stomach stands up”) which expresses a feeling of anger. The English phrases “I’ve had a gutsful” or “I can’t stomach him” or “Quit your bellyaching” come to mind: all of them associating unpleasant gastric sensations with unpleasant emotions, in particular irritation, disgust or anger.
Usually scowled through gritted teeth, accent on the second syllable, the phrase mukatsuku is one that almost ranks up there in terms of frequency of use with other phrases from happier moments like kawaii and sugoi, or the only two words in Japan used to describe the weather: atsui and samui.
However, as with all such words, if you’re not a native speaker, a little caution as to where and when you use the intense "mukatsuku" is advisable!
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