Irritability is a term used to describe feelings of anger, annoyance and impatience, and is commonly experienced by individuals in daily life. However, there are diverse conceptualizations of irritability in public and clinical research, which often result in confusing irritability with anger and other overlapping concepts. This, in turn, leads to a lack of conceptual clarity. Accordingly, the purpose of this concept analysis was to explore the irritability concept, including its definitions, defining characteristics, antecedents, consequences and empirical referents. The findings showed that irritability is predominantly conceptualized as a psychophysiological concept in the literature. We demonstrated that irritability can be differentiated from overlapping concepts like anger by qualities, such as 'unpredictability and lowered emotion control', 'lowered threshold for negative emotional stimuli', 'being manifested in response to frustrative situations or physiological needs' and 'experience of disproportionate and unjustified emotional irritation'. Importantly, severe irritability prospectively predicts psychiatric disorders and greater impairments in health, financial, educational and social functioning in individuals. Taken together, our analysis showed that one should take into account the context, duration, intensity and importantly outcomes, when assessing irritability in an individual. Considering these findings and the presence of irritability in nursing practice, it is crucial for nurses to recognize and successfully identify this concept in the nursing care they provide within the diverse settings and patient populations.