adverb taking the 'to' particle, taru-adjective
frequently; very often; repeatedly
Describes actions or events occurring with high frequency, often in a somewhat formal or literary register. Commonly used with the particle と as an adverb.
彼は頻々と海外に出張する。
He frequently goes on business trips abroad.
この地域では地震が頻々と発生している。
Earthquakes occur very often in this region.
Reduplication of 頻 (ひん, 'frequent'), forming an adverb/adjective meaning 'frequently'.