The term "piecemealed" typically refers to something that has been put together haphazardly or in a disjointed manner. If you are looking for synonyms for "piecemealed," then words such as fragmented, patchy, incomplete, disjointed, and sporadic might come to mind. Other words that are similar in meaning include disconnected, erratic, jumbled, and scattered. The opposite of "piecemealed" might be words like cohesive, unified, and integrated. Depending on the context in which you are using the word, you might also consider using phrases like "cobbled together" or "thrown together" to convey a similar meaning.