What is a post pattern in football?

Answer 1

The post pattern is a route a receiver will run. The receiver will be between the hash marks and the side line when setting up. They will run straight down the field for anywhere from 7-15 yards and the cut towards the middle of the field on a 45 degree angle. It is called a post pattern because the middle of the field is where the goal posts are found.

Answer 2

On a post route, the receiver breaks toward the middle of the field in a attempt to split safties running a cover 2. In the event the defense is running cover 3, this would have him running straight at a defender so instead he takes a steeper angle called a "skinny" post, trying to split the deep middle and deep 3rd defenders. In short, it's a post route that's more up the field and less across.