1. a small rodent with a long tail, typically larger than a mouse
2. a person who betrays or informs on others
Usage: informal

1. to inform on someone; to betray
Usage: informal
2. to hunt or catch rats

Examples

• The old barn was infested with rats.
• She set traps to catch the rats in her basement.
• Don't trust him – he's a rat who will sell you out.
• The prisoner ratted on his cellmate to get a lighter sentence.
• The terrier was bred for ratting in warehouses.
• Rats are intelligent animals that can learn complex tasks.