The phrase "in on a landslide" generally refers to achieving a significant victory or success. There are several synonyms that can be used interchangeably with this phrase. One such synonym is 'swept away'. This implies being carried along by a wave of success or momentum. Other synonyms include 'triumphant', 'victorious', and 'dominant', all of which signify achieving a resounding victory. Additionally, the phrase 'on a winning streak' can be used to describe consistent success over a period of time. Whatever synonym one chooses, the central idea is the same - a person or team has achieved a significant victory and is on the path to continued success.