be fighting a losing battle

be fighting a losing battle

To be trying persistently and with great effort to do or achieve something that is ultimately doomed to fail. You're fighting a losing battle if you think you can convince Sarah to go to college. It looks like I'm fighting a losing battle trying to get a raise from my boss.
See also: battle, fight, losing
Farlex Dictionary of Idioms.

be fighting a losing battle

COMMON If you are fighting a losing battle, you are trying to achieve something, but you are very unlikely to succeed. Recent research by doctors in Los Angeles suggests that very overweight dieters may be fighting a losing battle. Theatres compete with the movies and DVDs and they're fighting a losing battle.
See also: battle, fight, losing
Collins COBUILD Idioms Dictionary, 3rd ed.
See also:
  • fight a losing battle
  • play a losing game
  • it'll (all) end in tears
  • it'll end in tears
  • end in tears
  • the sick man of
  • the sick man of (something or somewhere)
  • stop at
  • stop at (something)
  • keep after (someone or something)