The word "co-wing" is not commonly used in the English language and does not have any established antonyms. It is possible to create antonyms by modifying the prefix "co-" which means "jointly" or "together." For example, antonyms could be "separate wings," "different wings," "independent wings," or "opposing wings." However, these antonyms would not be widely recognized and may not accurately convey the meaning of the original word. It is important to use common and well-established vocabulary to communicate clearly and effectively in any language.