(informal, derogatory) A foolish or silly person.If that goofball would put half the effort into her studies as she does into her juggling, she might do very well.
1953 April 27, "Capsules," Time:Strong Cobb & Co. of Cleveland announced a new barbiturate which in overlarge doses will turn the stomachs of "goofball" addicts and would-be suicides.
Adjective
goofball
Silly.He announced, with his usual goofball humor, that he'd like to marry me!