A person with intelligence is often referred to as a 'SPY' in three letters: 'SPY'. A SPY is someone who gathers information covertly and is often employed by governments or organizations to investigate and report on activities of other individuals or groups. Spies are usually highly trained and have a great deal of knowledge and experience in the field of intelligence gathering. They are often tasked with uncovering secrets, gathering evidence, and providing intelligence to their employers.