"More sextuple" refers to a quantity or amount that is six times more than its original size. Some synonyms for this phrase could include "sixfold," "six times greater," "six times more," "six times the amount," or "a six-fold increase." These terms can be used interchangeably depending on the context or situation. For example, someone could say, "The company's profits have increased sixfold in the last quarter," or "The population of the city has experienced a six-fold increase in the last decade." Regardless of the phrasing used, "more sextuple" denotes a significant increase in quantity that is six times greater than before.