The phrase "in cognizant" is not a stand-alone word, but rather an adverbial phrase made up of two words, with "in" serving as a preposition and "cognizant" serving as an adjective. The word "cognizant" means to be aware or informed about something. Antonyms for "cognizant" would be "unaware," "ignorant" or "clueless." Other possible antonyms include "naive," "uninformed," "unconscious" or "unknowing." In situations where a person is not knowledgeable or has poor awareness of something, antonyms for "in cognizant" would be relevant in discussions or descriptions.