정신력이 · 정신력을
mental strength, willpower, mental toughness
Example
마라톤에서는 체력만큼 정신력도 아주 중요해요.
In a marathon, mental strength matters just as much as stamina.
Word parts
정 essence+신 spirit+력 power
정신 'mind, spirit' plus -력 'power'.
Good to know
Pronounced [정신녁], not [정실력] — an exception to the usual ㄴ+ㄹ rule.
Related words