to not succeed at something
If you don't study, you might fail the test.
to not pass a test or exam
You will fail if you don't answer the questions correctly.
to not do something you should do
He never fails to say thank you.
to stop working properly
The engine might fail if not maintained.
to become weak or less effective
His health began to fail as he grew older.
to disappoint someone or not help when needed
Don't fail your friends when they need you.
to not be enough when needed
The crops will fail if there is no rain.
to be unable to continue operating
Many small businesses fail in their first year.
a result of not passing a test or exam
Getting a fail means you need to try again.
a mistake or lack of success
The project was a complete fail from the start.