a head up - A head up is when someone tells you something bad is coming

A head up is when someone tells you something bad is coming and you're not ready for it.

I got a head up when my teacher said, 'You're going to fail this class.'

He got a head up when his friend said, 'You're going to get suspended again.'

She got a head up when her mom said, 'If you don't stop fighting, you're going to get grounded.'