informer
UK: ɪnˈfɔːmə | US: ɪnˈfɔːrmər
n. a person who informs, especially secretly, against others
n. a source that provides information or data
The word "informer" combines the verb "inform," derived from Latin informare ("to shape, educate, give form to"), with the agentive suffix "-er," indicating a person who performs the action. Originally, "inform" meant to impart knowledge or shape someone's understanding. Over time, "informer" specialized to denote someone who provides information, often covertly, reflecting societal roles in legal or secretive contexts.
The police relied on an informer to uncover the drug ring.
Journalists protect their informers to ensure confidentiality.
He was labeled an informer after testifying against his colleagues.
The informer provided crucial details about the planned robbery.
In historical contexts, informers were often feared and mistrusted.