Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Encyclopedia.
on (one's) tail
Following or pursuing very close behind someone. The cops are on our tail—we have to lose them in the woods. Why is this guy sitting on my tail when I'm already going over the speed limit?
on someone's tail
Inf. Fig. following someone closely. (See also on someone's heels.) There is a huge truck on my tail. What should I do? Keep on her tail and don't let her out of your sight.