According to Wikipedia
Anxiety (also called angst or worry) is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness, and dread.Anxiety is considered to be a normal reaction to a stressor. It may help someone to deal with a difficult situation by prompting them to cope with it. When anxiety becomes excessive, it may fall under the classification of an anxiety disorder.