Full of beans is an informal English idiom that means lively, energetic, cheerful, or full of enthusiasm. It is usually said about a person, especially someone who seems unusually active or excited.
A likely origin comes from ideas about feeding horses. In earlier usage, beans were thought of as strong fuel for working animals. A horse that had been fed well had plenty of energy, so the image of being full of beans gradually became linked to being active and spirited.
Today, the phrase is common in friendly, everyday English. It often suggests healthy energy rather than aggression or stress.
- The children were full of beans after lunch.
- Even at 7 a.m., Maya was full of beans and ready to start hiking.
You would not usually use this phrase for quiet concentration or serious determination. It fits better when someone is visibly lively, playful, or bursting with energy.