1
general::
Phrase(s): monkey business [and] funny business
silliness; dishonest tricks. • That’s enough monkey business. Now, settle down. • Stop the funny business. This is serious!
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Silly, mischievous, or deceitful conduct, as in The teacher told the children to cut out the monkey business and get to work, or I don't trust that lawyer? there's some monkey business going on. This expression transfers the tricks of monkeys to human behavior. [Late 1800s]
American Heritage Idioms