What does 功夫 (gōng fu) mean in English?

Card 334HSK 2010 Level 5334/1311
CARD334
PROGRESS25%
功夫
gōng fu
skill; art; kung fu; labor; effort

Reveal: Click/Space/Enter/↑↓/w/s/j/kNavigate: ←→/h/l/a/d