間諜 — meaning in English

jiàn dié

English meaning

informant noun A person who secretly gives confidential information to authorities, such as the police.
nark noun (informal) Someone who secretly gives information to the police.
snitch verb To inform on someone, often betraying a friend or group.
spy noun A person who secretly gathers information about others, often for a government or rival organization.
stooge noun Someone who lets themselves be used by others, usually to take the blame or do the dirty work.

間諜 is used for these senses in English:

informant One who relays confidential information to someone, especially to the police; an informer.
nark (UK, Ireland) A police spy or informer.
snitch (slang) An informer, one who betrays their group.
spy (espionage) A person who secretly watches and examines the actions of other individuals or organizations and gathers information on them (usually to gain an advantage).
stooge A secret informant for police.
stool pigeon (slang, obsolete, gambling) A decoy used in a crooked gambling game.

noun A person who secretly gives confidential information to authorities, such as the police.
noun A native speaker who helps linguists by providing examples and judgments about a language.