lost cause
Plural
lost causes
1
a thing or person that is impossible to improve or succeed
- After numerous failed attempts, the project seemed like a lost cause.
- The once-thriving business had become a lost cause due to poor management.
- Trying to convince him otherwise felt like a lost cause.
- The deteriorating relationship was seen as a lost cause by both partners.
- The neglected garden was viewed as a lost cause by the new homeowners.