When it comes to confidentiality, the word supersecret is an excellent descriptor. However, sometimes you need to switch up your vocabulary and find alternate synonyms. One option could be clandestine, which implies an element of secrecy or concealment. Another option is covert, which indicates something hidden, disguised, or not openly shared. Confidentiality could also be described as privy, implying exclusive knowledge or information available only to a select few. The phrase "eyes only" or "for your eyes only" are also effective synonyms for supersecret, meaning that the information is intended for one person's knowledge only. Overall, there are many options to describe something that is supersecret while maintaining its level of confidentiality.