excitable
Easily becomes very excited or emotional about things.
Excitable means easily stirred up or quick to show enthusiasm, nervousness, or other strong emotions. An excitable puppy bounces and wiggles at the slightest hint of a walk. An excitable child might jump up and down when hearing about a field trip, barely able to contain their energy.
Being excitable isn't necessarily good or bad. It just means your emotions and reactions come quickly and visibly. Some people are naturally more excitable than others. An excitable scientist might rush to share a new discovery with colleagues, talking rapidly and gesturing with excitement. An excitable sports fan might leap from their seat at every close play.
The word often describes a general temperament rather than a single moment. You might say your friend is excitable because she gets enthusiastic about new ideas easily, while her calmer brother takes things more in stride. Teachers sometimes ask excitable students to settle down if their energy disrupts the class.
Related words include excitability (the tendency to become excited) and excitement (the feeling itself). Notice that being excitable is about how easily you get excited. The word captures the speed and frequency of your reactions: excitable people reach excitement more quickly and more often than others.