When it comes to finding synonyms for the term "rig up," several phrases can convey similar meanings. Some of the most common synonyms include assemble, construct, build, create, fashion, fabricate, devise, and engineer. These verbs all hold a similar sense of constructing or creating something from pieces or parts. Other alternatives include patch together, put together, cobble together, fix up, and jury-rig, which are all terms for creating something quickly in a makeshift way. Overall, if you need to express the idea of constructing or creating something, these synonyms for "rig up" provide several options to work with.