to accompany one to the point of departure for a trip and say good-bye upon departure. We went to the train station to see Andy off. We saw off all the scouts going to camp.
to accompany someone who is leaving something; to escort someone away from something. I saw the elderly lady off the station platform safely. The emcee saw the contestants off the stage.
to go with someone to the place where they will begin a trip My parents saw me off at the airport.Families gathered at the dock to see off the sailors.