hardy, stalwart, stout, sturdy -- (having rugged physical strength; inured to fatigue or hardships; "hardy explorers of northern Canada"; "proud of her tall stalwart son"; "stout seamen"; "sturdy young athletes")
uncompromising, sturdy, inflexible -- (not making concessions; "took an uncompromising stance in the peace talks"; "uncompromising honesty")
sturdy, tough -- (substantially made or constructed; "sturdy steel shelves"; "sturdy canvas"; "a tough all-weather fabric"; "some plastics are as tough as metal")
(Sound)
