Anxiety is a feeling of discomfort, such as worry or fear, that may be mild or severe but that lasts over time.(1)
If a transient fear is a normal reaction to a stressful situation (like taking an exam, a job interview…), anxiety is an excessive but transient reaction to a situation felt to be a threat (1).
Anxiety disorders are different from transient fear and anxiety, they are repetitive, persist over time, occur unrelated to a real danger or threat and create suffering in those affected (1).