free-running adjective 1free running noun 1forms 4 adjective1 •Moving freely and smoothly.As to any suggestion that Stroudley's engines were not free-running at high speed, this was of little moment with 60 m.p.h. laid down as the limit at that time. — 1941 free running noun1 •The activity of combining parkour with gymnastics to pass obstacles and demonstrate athletic talent, most often in urban environments. formsfreer running · freer-running · freest running · freest-running