Synonyms and related words :
acting, active, agential, agentival, agentive, at work, behavioral, effective, effectual, efficacious, efficient, functional, functioning, go, going, going on, in exercise, in force, in hand, in operation, in play, in practice, in process, in the works, inaction, managerial, manipulational, on foot, on the fire, ongoing, operating, operative, performing, practical, practicing, running, serving, working