Irritable/ˈɪrɪtəbl/ Definition 1 of 3Pro Tip 1/3Negative Tone Used when someone's mood is negatively affected, often implies impatience or rudeness. Avoid asking her for favors when she's irritable. Pro Tip 2/3Temporary State Can describe a temporary mood, not necessarily a personality trait. He's usually cheerful, but he's quite irritable today. Pro Tip 3/3Not for Formality Avoid using in formal writing; find a more formal synonym if needed. During the meeting, she appeared unusually impatient.