집중력이 · 집중력을
concentration, focus
Example
잠을 충분히 못 자면 집중력이 떨어져요.
If you don't get enough sleep, your concentration drops.
Word parts
집 gather+중 center+력 power
Literally 'power to gather into the center'.
Good to know
Pronounced [집쭝녁]; common pairs: 집중력이 좋다/떨어지다/높이다.