noun
upstart; mushroom millionaire
Refers to someone who has suddenly risen to wealth or prominence, often with a nuance of lacking refinement or old money status. Somewhat dated; more common in literary or historical contexts.
彼は一代で財を成した出来星だ。
He is an upstart who made his fortune in one generation.
古い小説には、出来星と蔑まれる成金がよく登場する。
In old novels, nouveau riche characters derided as upstarts often appear.