Final answer:
Neuroticism is the term for a trait associated with emotional negativity, pessimism, and irritability, noting people high in neuroticism are more likely to experience emotional instability and negative emotions.
Step-by-step explanation:
The term for the trait characterized by emotional negativity, pessimism, and irritability is neuroticism. Neuroticism is one of the five major dimensions of personality and is associated with the tendency to experience negative emotions such as anger, anxiety, and sadness. People high in neuroticism are more susceptible to emotional instability and may exhibit behaviors that are impulsive, angry, or hostile. In contrast, those with low levels of neuroticism tend to be more calm and even-tempered. Studies, such as those by Watson and Clark (1984), have also linked high levels of neuroticism with anxious and unhappy feelings, and the association has extended to physical health. Research has found that high neuroticism can be a risk factor for chronic health issues and mortality, as well as a notable risk factor for cardiovascular disorders.