The antonyms for "pull something apart" are "assemble," "put together," "construct," and "build." These words denote the opposite of tearing something apart or dismantling it. When we assemble something, we are joining its components to form a whole. It could be a puzzle, a toy, or a piece of furniture. Putting something together indicates that we are reuniting pieces to make an object functional or usable. Constructing something is the process of designing and building a structure, be it a house, skyscraper or bridge. And, building something is the process of creating something, such as a business or a brand, with the aim of making it bigger and better.