No funny business

Meaning

This is a warning to act appropriately and follow the rules. It is often said by parents to children, or in a work environment to ensure professional conduct.

Stern, authoritative

Used in a sentence

• I am leaving you kids home for an hour, and I want no funny business.
• The teacher told the class there would be no funny business during the test.
• We want this merger to go smoothly, so no funny business with the accounts.