- An act of driving dangerously close behind another vehicle.
- A tailgate party (a social event held on and around the open tailgate of a vehicle)
- Present participle of tailgate.
Just as a driver can tailgate another driver’s car by following too closely, in the security sense, tailgating means to compromise physical security by following somebody through a door meant to keep out intruders. Tailgating is actually a form of social engineering, whereby someone who is not authorized to enter a particular area does so by following closely behind someone who is authorized.