Usage patterns
強靭な精神a tough, resilient spirit
She overcame the hardship with a tough, resilient spirit.
強靭な肉体a strong, resilient body
Athletes train every day to maintain a strong, resilient body.
強靭な意志an unbreakable will
He achieved his goal thanks to his unbreakable will.
強靭さを持つto possess toughness/resilience
This material possesses a surprising degree of toughness.