余力

energy left over (to do sth else)

surname Yu

(archaic) I / me / variant of 餘|余[yu2], surplus

extra / surplus / remaining / remainder after division / (following numerical value) or more / in excess of (some number) / residue (math.) / after / I / me

power / force / strength / ability / strenuously

to spare no pains or effort (idiom); to do one's utmost

after that, any remaining energy (idiom from Analects); time for extracurricular activities

see 心有餘而力不足|心有余而力不足[xin1 you3 yu2 er2 li4 bu4 zu2]