When something is very makeshift and poorly put together, it can be described as the "most juryrigged." However, there are many other synonyms that can be used to convey the same meaning. Words such as slapdash, haphazard, cobbled together, improvised, ramshackle, and makeshift can all be used to describe something that has been quickly put together without much thought or care. These words all convey a sense of imperfection and lack of attention to detail, and can be useful when describing anything from a shoddy repair job to an impromptu solution to a problem. Whatever word you choose to use, it's important to convey a sense of the object's imperfection and lack of planning.