From Longman Dictionary of Contemporary Englishon-offˌon-ˈoff adjective [only before noun] 1 happening sometimes and not at other times an on-off relationship She had an on-off obsession with Mikey.2 an on-off switch is the thing you press to make a piece of electrical equipment start and stop working
Examples from the Corpus
on-off• They had even had an on-off affair and Harriet suspected he was in love with her.• The on-off and zoom buttons are positioned separately, adjacent to the handgrip.• That can not be done on an on-off basis.• She had witnessed the on-off charm for herself when he had thought himself alone in the Feathers' coffee-room.• Computers, Fletcher maintains, always have their on-off switch on the back.• When used in pillar drill, it is often very difficult to reach the on-off switch with one hand on the lever.• The on-off throttle is still a little noticeable on the road but you can live with it. 