What Does “shot across the bow” mean?
Definition:
The phrase a shot across the bow is an idiomatic expression that indicates a warning to stop doing something.
The origin of the phrase comes from the naval practices. It is a sort of a military and/or police warning shot which is an intentionally harmless artillery shot with intent to enact direct compliance and order to a hostile perpetrator or enemy forces.
Example(s)
The way the teacher scolded the kids after class is a shot across the bow.
This idiom is in the war category.