adverb taking the 'to' particle, taru-adjective
springing up; with alacrity; resolutely
Formal literary term describing a sudden, energetic movement or a decisive, spirited action. Often used with と (to) as an adverb.
彼は席を蹶然と立った。
He sprang up from his seat.
蹶然として行動を起こす。
To take action resolutely.