Unknown/ˌʌnˈnəʊn/ Definition 1 of 4Pro Tip 1/3Emotional Distance Used when lacking emotional connection or when something feels unfamiliar. He felt unknown emotions towards the situation. Pro Tip 2/3Impersonal Interaction Describes a lack of personal knowledge about people or places. The letter was signed by an unknown admirer. Pro Tip 3/3Descriptive Uncertainty Highlights lack of information or detail about an object or concept. The substance was an unknown compound to the scientists.