A frolic is a light-hearted, fun, often silly activity. To frolic is to cavort, romp, or run around — to have fun.
Ever see two puppies playing in the park, wrestling, chasing, and just having a ball with each other? You could say they're having a frolic or frolicking. When we frolic, we're having a fun time. Flying a kite, playing frisbee, skipping around, and having a picnic could be examples of frolics. If things are grim and serious, or you're in a bad mood, then it's tough to frolic. This is one of the happiest, most playful words in the dictionary.