What feeling is characterized by irritation or humiliation due to disappointment?

The term that best describes the feeling of irritation or humiliation resulting from disappointment is "chagrin." This word encompasses a sense of distress or embarrassment that arises when one's plans do not go as expected or when one is made to feel foolish or defeated by circumstances. It conveys a personal emotional response to a particular setback or unfulfilled expectation, often leading to a mix of frustration and self-doubt.

In contrast, the other terms listed do not capture this specific emotional nuance. "Fracas" refers to a noisy argument or fight, which involves conflict rather than a personal emotional response. "Pandemonium" describes a state of chaos and uproar, indicating disorder among a group rather than individual feelings of disappointment. "Grotesque," on the other hand, pertains to something that is comically or repulsively distorted, which has a different meaning and does not relate to the feeling of chagrin. Thus, "chagrin" is the most appropriate choice for conveying that particular emotional state of irritation or humiliation.