Unperceiving is an 11-letter term that can be defined by the words INATTENTIVE, NEGLIGENT, and CARELESS. It means to be unaware or not paying attention to something, often due to a lack of care or interest. INATTENTIVE means not giving enough attention or thought to something, NEGLIGENT means failing to take proper care of something, and CARELESS means not taking enough care or thought when doing something. Together, these words describe someone who is unperceiving, or not paying attention to their surroundings.