How would you describe someone who is "irascible"?

The term "irascible" is used to describe someone who is easily provoked to anger or tends to get angry quickly. This characteristic suggests a short temper or a propensity to respond to situations with agitation or hostility. Therefore, the description of being "quickly aroused to anger" captures the essence of the word perfectly.

The other options provided represent characteristics that are opposite to the definition of "irascible." Being calm and composed, patient and understanding, or indifferent to emotions indicates a level of emotional control, tolerance, or detachment that does not align with the impulsiveness associated with irascibility. Thus, these alternatives do not fit the definition of the word being assessed.