See: OFF AND ON.
{adv.} Not regularly; occasionally; sometimes. * /Joan wrote to a pen pal in England off and on for several years./ * /It rained off and on all day./ - Sometimes used with hyphens like an adjective. * /A worn-out cord may make a hearing aid work in an off-and-on way./ Compare: BY FITS AND STARTS, FROM TIME TO TIME, NOW AND THEN.