one's superior's anger; imperial wrath
Idiomatic expression originating from a Chinese legend about a dragon's reverse scale that, when touched, enrages the dragon. In modern Japanese, it refers to provoking the anger of a superior or powerful person. Often used in the phrase 逆鱗に触れる (to incur someone's wrath).
See also: 逆鱗に触れる
I incurred the president's wrath and the project was canceled.
He made a remark that touched his boss's reverse scale.
imperial wrath (original meaning)
Original meaning from the Chinese legend, specifically referring to the anger of an emperor or sovereign. Rarely used independently in modern Japanese; the idiomatic sense is dominant.
Originally, 'gekirin' referred to the anger of the emperor.