goofball goofball /ˈɡuːfˌbɔːl/

noun

1. [Informal, N. American] A person who amuses others by ridiculous behavior  ( buffoon , goof [Informal] , goofball [Informal, N. American] , clown , merry andrew [Archaic] )
   a person who amuses others by ridiculous behavior
   
   
2. A man who is a stupid incompetent fool  ( bozo , cuckoo , fathead , goof , goofball , goose , jackass , twat , zany )
   a man who is a stupid incompetent fool
     John's stubborn behavior earned him the nickname "jackass" among his friends.
   John's stubborn behavior earned him the nickname "jackass" among his friends.