taru-adjective, adverb taking the 'to' particle
brilliant and quick-witted; sparkling with intelligence
Describes a person whose intelligence is lively, sharp, and full of energy. Often used in literary or formal descriptions of someone's mental agility.
彼の議論は才気溌剌としていて、聞く者を圧倒した。
His arguments were so brilliant and lively that they overwhelmed the listeners.
若い棋士が才気溌剌たる手を次々と繰り出した。
The young shogi player produced one sparklingly brilliant move after another.
Compound of 才気 (intelligence, wit) and 溌剌 (lively, energetic). 溌剌 is a reduplicative compound of 溌 (splash, energetic) and 剌 (oppose, sharp), together conveying a sense of vigorous, sparkling energy.