noun
Refers to political or social power and influence, often wielded by individuals or groups in positions of authority. Slightly formal.
彼は政界で絶大な権勢を振るった。
He wielded enormous power in the political world.
権勢を誇る一族がこの地域を支配していた。
A family boasting great influence controlled this region.
Compound of 権 (authority, right) and 勢 (power, force). The exact historical derivation is uncertain, but the combination naturally conveys the idea of authoritative influence.