rigid(rigorous, unbending) adjective [UK: ˈrɪ.dʒɪd] [US: ˈrɪ.dʒəd]The new TV host is a little rigid. = Den nye programledaren är lite stel.
stiff [stiffer, stiffest](of an object, rigid, hard to bend, inflexible) adjective [UK: stɪf] [US: ˈstɪf]Their muscles are stiff. = Deras muskler är stela.