The word "unalphabetical" typically refers to something that is not arranged in alphabetical order. Therefore, some antonyms for this word may include "alphabetical," "ordered," "systematic," "sequential," and "organized." These antonyms would describe something that is arranged in a specific order, whether it is by the alphabet, numerical system, or other predetermined method. Another antonym could be "rational," which implies that something has been thought through and logically arranged. On the other hand, "chaotic," "disorganized," "haphazard," and "random" would all be synonyms for "unalphabetical.