'Crudded up' is an expression that suggests something that is messy, unclear or unorganized. Antonyms for this term include clean, tidy, organized, and neat. The opposite of 'crudded up' would be a situation, place, or item that is pristine, well-maintained, and in order. Some additional antonyms for 'crudded up' could be elegant, polished, groomed, sleek, and refined. At times, 'crudded up' describes something with a grungy or gritty vibe. Antonyms for this particular connotation could be civilized, refined, cultured, and sophisticated.