Other forms: waspishly
If someone is acting irritable or crabby, you can describe them as waspish. Your sister's waspish complaints about dinner aren't likely to convince your dad to order pizza for her instead.
This adjective comes from the word wasp and the notion that wasps are spiteful and ill-tempered, stinging petulantly when they feel cranky. If someone calls you waspish, that's what they mean — you're easily irritated. It's less common than it once was (waspish has been used since at least the mid-1500s), but it's still a great way to describe anyone who's quick to express their anger.