taru-adjective, adverb taking the 'to' particle
prosperity on the rise; fortune reaching its peak
A somewhat literary or formal expression describing one's luck or fortune as flourishing or at its height. Often used in set phrases or auspicious contexts.
彼の運勢隆々たる活躍ぶりには目を見張るものがある。
His flourishing success is truly remarkable.
今年は運勢隆々として、次々と良いことが起こった。
This year, my fortune has been on the rise, and good things keep happening one after another.
Compound of 運勢 (fortune, luck) and 隆々 (prosperous, flourishing). The exact historical derivation is uncertain, but the phrase is used in literary and formal contexts to describe rising fortune.