adj. 25B6; adjective
the child was vigorous : ROBUST, healthy, hale and hearty, strong, sturdy, fit; hardy, tough, athletic; bouncing, thriving, flourishing, blooming; energetic, lively, active, perky, spirited, vibrant, vital, zestful; informal peppy, bouncy, in the pink.
a vigorous defence of policy : STRENUOUS, powerful, forceful, spirited, mettlesome, determined, aggressive, eager, zealous, ardent, fervent, vehement, passionate; tough, blunt, hard-hitting; informal punchy.
weak, feeble.