The phrase "most withit" is used to describe someone who is fashionably current or up-to-date with the latest trends. However, there are a few antonyms for this term. Firstly, someone who is "outdated" may not be seen as withit. Another antonym is "unfashionable," indicating the opposite of someone who is up-to-date with fashion. Another term that can be used as an antonym for "most withit" is "old-fashioned," which implies that someone is not adopting contemporary fashions or trends. Lastly, someone who is "behind the times" or "out of touch" may also be seen as an antonym for "most withit.