frolic

(noun) gay or light-hearted recreational activity for diversion or amusement. Synonyms: play, romp, gambol, caper. Examples: "It was all done in play." "Their frolic in the surf threatened to become ugly."

(verb) play boisterously. Synonyms: lark, rollick, skylark, disport, sport, cavort, gambol, frisk, romp, run around, lark about. Examples: "The children frolicked in the garden." "The gamboling lambs in the meadows." "The toddlers romped in the playroom."