Irascible often describes someone with a short temper and impulsive reactions. The irascible chef threw a pan when the dish was slightly overcooked.
Pro Tip 2/3
Negative Connotation
Using 'irascible' suggests a negative opinion about someone's personality. The irascible witness made the courtroom tense with his outbursts.
Pro Tip 3/3
Personality Trait
Irascible is often used to indicate a characteristic trait, not just a temporary mood. Despite his brilliant mind, the inventor was known to be irascible.