Traffic  —n. 1 vehicles moving on a public highway or in the air or at sea. 2 (usu. Foll. By in) trade, esp. Illegal (drugs traffic). 3 coming and going of people or goods by road, rail, air, sea, etc. 4 dealings between people etc. (had no traffic with them). 5 messages etc. Transmitted through a communications system; volume of this. —v. (-ck-) 1 (usu. Foll. By in) deal in something, esp. Illegally. 2 deal in; barter.  trafficker n. [french from italian]