informant
//ɪnˈfɔːmənt//
Noun
informantSingular
informantsPlural
1
A person who provides information to authorities, especially about criminal activities or to the police.
The police relied on an informant to gather evidence about the drug ring.
2
A person who provides data or information to a researcher, especially in linguistics or anthropology.
The linguist interviewed several native informants to document the endangered language.