The phrase "more on and off" refers to something that happens intermittently, with periods of activity followed by periods of inactivity. Some synonyms for this phrase include sporadic, occasional, irregular, fitful, and intermittent. These words all convey the idea of something happening in a scattered or irregular pattern. Another related phrase is "on again, off again," which has a similar meaning and implies a lack of consistency or reliability. Whether you're describing an erratic schedule, a temperamental appliance, or a fickle friend, using one of these synonyms can add clarity and nuance to your writing or conversation.