"On occasion" is a phrase commonly used to describe events or actions that happen infrequently or sporadically. However, there are several synonyms that can be used in its place, such as "from time to time," "once in a while," "now and then," "every now and then," "occasionally," "intermittently," "sporadically," and "at intervals." These synonyms help to add variety and specificity to one's writing or speaking, allowing for a more vivid and engaging description of the subject matter. Whether used in casual conversation or formal writing, using synonyms for "on occasion" can help to add interest and depth to any text or speech.