fail

conjugation failing - failed - failed

verb: to be unsuccessful in achieving a goal
- If you do not study, you might fail the exam.
verb: to be unable to do what is expected or required
- The engine will fail if it is not properly maintained.
noun: a grade or result indicating that a student has not passed an examination or course
- Receiving a fail on the assignment was a major setback.
verb: to become weak, decline, or lose vigor
- The ancient empire began to fail under the pressure of invading forces.