Irritable

Irritable is an adjective used to describe a person who becomes easily annoyed or angered, or a state in which a body or tissue is highly responsive to stimuli. In everyday language it characterizes mood and behavior, while in medical or scientific contexts it can refer to heightened sensitivity or reactivity of cells or tissues.

Etymology: the word derives from Latin irritabilis, from irritare meaning “to provoke, excite.” The related noun irritability refers to the tendency to respond to stimuli or to the condition of being easily irritated.

Mood and clinical context: in clinical settings, irritability is a non-specific symptom that can accompany stress, fatigue, pain, illness, hormonal changes, or withdrawal from substances. It may appear with anxiety, depression, bipolar disorder, premenstrual syndrome, or certain medications. It is typically described as impatience, irritability, or a low tolerance for frustration. While irritability can be a feature of several conditions, it is not by itself a diagnosis.

Physiological context: in physiology, irritability describes the inherent responsiveness of a tissue to a stimulus. Nerve cells and muscle fibers are considered irritable because they respond to electrical or chemical signals with action potentials or contractions. Factors such as electrolyte balance, hydration, temperature, or injury can influence tissue irritability and the magnitude of the response.