Health Description The definition of Anxiety is a feeling of worry, nervousness, or unease, typically about an imminent event or something with an uncertain outcome. Anxiety can come about after stressful events. Because of these past events anxiety may be triggered by any future related events. For some, a word, a song, a person, a place, or thing can trigger anxiety if it relates to a stressful or traumatic event in their past. Some anxiety can be “untrained” and prevented. Some symptoms of anxiety can be reduced by using essential oils and aromatherapy.