noun
Almost exclusively used in the idiom 一旗揚げる (ひとはたあげる), meaning 'to start a new enterprise' or 'to make a name for oneself'. The standalone noun is rare.
See also: 一旗揚げる
「一旗揚げる」という表現で使われる。
It is used in the expression 一旗揚げる.
彼は独立して一旗揚げようとしている。
He is trying to start his own business and make a name for himself.
This is the idiomatic phrase where 一旗 appears; it means 'to launch a venture' or 'to rise in the world'.
Compound of 一 (one) and 旗 (flag). The exact origin of the idiomatic use is uncertain, but it likely refers to raising one's own banner as a symbol of starting a new endeavor.