A person who secretly watches and examines the actions of other individuals or organizations and gathers information on them (usually to gain an advantage).

(intransitive) To act as a spy. / (transitive) To spot; to catch sight of. / (intransitive) To search narrowly; to scrutinize.

To watch secretly or covertly; to surveil.

Obsolete spelling of spied; simple past tense and past participle of spy

plural of spying

present participle of spy

espionage; the act of secretly gathering information

Money paid for secret intelligence.

plural of spy plane

(informal) A genre of science fiction involving secret agents.