Learner's definition of WARNING
1 : something (such as an action or a statement) that tells someone about possible danger or trouble
She gave me a warning about the difficulties of the job.
There were storm warnings [=warnings that a storm was approaching] issued for the area.
She issued a stern warning against making changes too quickly.
Let that be a warning to you.
We had no warning of the dangers that were ahead of us.
Without any warning she turned around and ran.
The storm struck without warning.
2 [count] : a statement that tells a person that bad or wrong behavior will be punished if it happens again
— warningadjective,always used before a noun