终日不倦

終日不倦
zhōngrìbùjuàn

to not get tired the whole day long; to do something all day and not get tired

Wiktionary

Entry Composition

1 终日 zhōngrì all day long
2 不倦 bùjuàn
  1. tireless
  2. untiring
  3. indefatigable