Antonyms for the word "inhabitually" would depend on the context in which the word is being used. If it refers to a negative or unhealthy habit, some possible antonyms could be "irregularly," "occasionally," "sporadically," or "infrequently." If the word has a positive connotation, like a good habit or routine, antonyms could be "rarely," "seldom," "inconsistently," or "uncommonly." Another possible antonym could be "habitually" itself, as it is an antonym of the root word "inhabitual," suggesting that the action is done regularly or frequently. Ultimately, it is important to consider the context in order to determine the appropriate antonym for "inhabitually.