When we think of the phrase "splinter up," we often associate it with the idea of breaking apart into smaller fragments. When looking for synonyms, we can explore words such as "shatter," "fracture," and "crumble." These words convey a sense of destruction and fragmentation, often associated with physical objects such as glass or wood. Additionally, words such as "disintegrate," "dismantle," and "decompose" can also be used to describe the process of breaking down into smaller parts. These words may be more applicable when referring to less tangible entities, such as relationships or ideas. Overall, when looking for synonyms for "splinter up," we can find many options that convey a sense of fragmentation or breakdown.