Marbleize is a unique word that is synonymous with the term veining, which refers to the marbled appearance of stones or fabrics. Another synonym is marblize, which refers to the use of paint or ink to create marble-like patterns. In addition, the term mottling can be used to describe the process of creating the appearance of marble on a surface such as paper or a wall. Swirl, streak, and smudge are other synonyms that can be used in certain contexts to describe the marbling effect. Overall, while marbleize may not have a broad range of synonyms, there are a few terms that can be used interchangeably depending on the context of the conversation.