1 A person that follows too closely behind another whilst driving.
2. A person that socialises behind a vehicle before entering a sporting event
3. A man that gets close behind a another and penetrates him anally.
1. person viewing multi car pile up "look at all those tailgaters!"
2. person viewing sporting stadium car park pre event "look at all those tailgaters!"
3. person looking in to a gay bar "look at all those tailgaters"