The opposite of "being habit of" would be "being unaccustomed to" or "being unfamiliar with." When we say someone has a habit of doing something, it means they have developed a regular pattern of behavior that comes naturally to them. In contrast, being unaccustomed to something means that one is not used to doing it, and it might require some effort to change one's habits to incorporate it. Being unfamiliar with something means that one has no experience or knowledge of it, which makes it challenging to develop a habit around it. Both of these antonyms indicate a lack of familiarity or comfort in a particular pattern of behavior.