coworker UK /ˌkəʊˈwɜː.kər/US /ˌkoʊˈwɝː.kɚ/ noun2 •Somebody with whom one works.He heard from a coworker that the company planned to merge those departments. •[before a noun] (Internet, disapproving) A person in the lowest common denominator, especially regarding popular culture.This is the most coworker movie I've ever seen. formscoworkers