竭力
jié lì · HSK 7
to do one's utmost
💪 竭 exhaust + 力 strength = drain every drop of strength = do one's utmost
竭 means to use up or exhaust (as a well runs dry); 力 is strength or effort. Together: pour out all your power until none is left, i.e. give it everything you've got.
力 — pictograph of a plow or arm muscle
力 originated as a pictograph of an ancient plow, the main tool requiring physical exertion in early agriculture. Some scholars also see it as a flexed arm showing muscle. From this concrete image it broadened to mean 'strength, power, force, effort'.