WordNet (r) 3.0 (2006):

tailgate
    n 1: a gate at the rear of a vehicle; can be lowered for loading
         [syn: tailgate, tailboard]
    v 1: follow at a dangerously close distance; "it is dangerous to
         tailgate another vehicle"

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "tailgate":
   around, bedog, chase, clasp, cling to, come after, come behind,
   dog, follow, follow close upon, go after, go behind, go with,
   hang about, heel, hound, hover over, huddle, hug, hug the shore,
   keep close to, lie by, march with, move behind, pursue, shadow,
   stand by, stay inshore, stay near, string along, tag, tag after,
   tag along, tail, trail, trail after, tread close upon