- trader (n.)
- "dealer, trafficker, one engaged in commerce," 1580s, agent noun from trade (v.).
- traffic (v.)
- 1540s, "to buy and sell," from traffic (n.) and preserving the original commercial sense. Related: Trafficked; trafficking; trafficker. The -k- is inserted to preserve the "k" sound of -c- before a suffix beginning in -i-, -y-, or -e- (compare picnic/picnicking, panic/panicky, shellacshellacked).