Robust  adj. (-er, -est) 1 strong and sturdy, esp. In physique or construction. 2 (of exercise, discipline, etc.) Vigorous, requiring strength. 3 (of mental attitude, argument, etc.) Straightforward, vigorous. 4 (of a statement, reply, etc.) Bold, firm, unyielding.  robustly adv. Robustness n. [latin robur strength]