being of crucial importance; "a pivotal event"; "Its pivotal location has also exposed it to periodic invasions"- Henry Kissinger; "the polar events of this study"; "a polar principal"
being the agent or cause; "determined who was the responsible party"; "termites were responsible for the damage"
worthy of or requiring responsibility or trust; or held accountable; "a responsible adult"; "responsible journalism"; "a responsible position"; "the captain is responsible for the ship's safety"; "the cabinet is responsible to the parliament"