A warning or caution about something, especially in a legal document.
The word caveat makes people think of being careful and paying attention to important details.
Examples:
The contract had a caveat about late payments.
She added a caveat to her advice.
The teacher gave a caveat about the difficult test.
The sign had a caveat: 'Beware of the dog!'
The scientist's report came with a caveat: 'This might not be true!'
He always gives a caveat before telling a scary story.