IPA: /ˈliːkər/
KK: /ˈlikər/
A person who reveals secret or confidential information, often to the public or the media.
The leaker provided important documents to the journalist.
Leaker → The word is formed from "leak" (from Old English *leacian*, meaning to flow or escape) and the suffix "-er" (meaning a person who). A leaker is a person who allows something to flow out or escape, often referring to information or secrets.
Think of someone who allows information to 'flow out' — that's what a leaker does.