1
general::
Phrase(s): goof off
to waste time. • John is always goofing off. • Quit goofing off and get to work!
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Shirk work or responsibility, loaf; fool around. For example, We were supposed to be studying but we were really goofing off, or If you ever feel like goofing off, please call me. This idiom was a synonym of GOOF UP during World War II, a usage that has died out. [Slang; 1920s] Also see GOOF AROUND.
American Heritage Idioms