Medical Definition of anxiety 1 a (1) : apprehensive uneasiness or nervousness usually over an impending or anticipated ill : a state of being anxious (2) : an abnormal and overwhelming sense of apprehension and fear often marked by physical signs (such as tension, sweating, and increased pulse rate), by doubt concerning the reality and nature of the threat, and by self …

anxiety [ ăng-zī ′ĭ-tē ] n. A state of uneasiness and apprehension, as about future uncertainties. A cause of anxiety. A state of intense apprehension, uncertainty, and fear resulting from the anticipation of a threatening event or situation, often to a degree that normal physical and psychological functioning is disrupted.