1.
overthrowing one's superiors; the lower overthrowing the higher
A situation where those of lower rank overthrow or surpass those above them. Originally a historical term describing the social upheaval of Japan's Sengoku period, now used broadly for any upset where an underdog defeats a favorite.
Usage
Originally a historical term describing the social phenomenon of the Sengoku period (15th-16th century) when lower-ranking warriors seized power from their superiors. In modern usage, it commonly describes upset victories in sports, business, or competitions.
Forms
下 (lower) + 剋 (to overcome) + 上 (upper)