Jugular is short for “jugular vein,” the major vein that brings blood from your head to your heart. You can also call any vulnerable area the jugular.
If you hear someone say, “Go for the jugular!” Watch out! A serious attack is coming. When lions attack prey, they chomp down on the jugular to kill the animal fast. If your jugular is cut, you could die very quickly without medical help. You can also call your neck and throat the jugular area. Because this is a vulnerable area, you can use this word for other vulnerable things, like a weak spot on a sports team.