Spied is the past tense of the verb spy, which means to watch someone or something secretly, usually to gather information. During the Cold War, governments spied on each other to learn military secrets. A spy might have spied through binoculars from a hidden position or spied on conversations using secret recording devices.

The word also has a gentler meaning: to catch sight of something, often something you've been looking for or something unexpected. A hiker might say “I spied a deer through the trees” or “She spied her lost keys under the couch.” People also use this meaning in games like I Spy, where players spot objects and give clues about them.

In stories about espionage, a character who spied for their country might be considered a hero or a traitor, depending on which side they're on. During World War II, brave individuals spied on enemy forces, risking their lives to send vital information back to their governments. The work required cleverness, courage, and the ability to blend in without raising suspicion.