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.
