ELI5: Explain Like I'm 5

Breach of contract

A breach of contract is when someone doesn't do what they said they were going to do in a contract. Let's say you and your friend make a contract that says if you lend them $10 then they will give you $15 back the next day. If they don't give you those $15 the next day, then they have broken the contract and that's called a breach of contract.