1. a person who reveals secret or confidential information to the public or media
2. something that allows liquid or gas to escape through a hole or crack

Examples

• The government is searching for the leaker who exposed the classified documents.
• A White House leaker revealed details about the private meeting.
• The journalist protected her source, refusing to identify the leaker.
• We need to fix this leaker in the roof before it rains again.
• The plumber found the leaker in the basement pipe.
• That old faucet is a constant leaker.