To gain sight of; to discover at a distance, or in a state of concealment; to espy; to see.
- An agent employed by a state to obtain secret information, especially of a military nature, concerning its potential or actual enemies.
- One employed by a company to obtain confidential information about its competitors.
- One who secretly keeps watch on another or others.
- An act of spying.
- To observe secretly with hostile intent.
- To discover by close observation.
- To catch sight of: spied the ship on the horizon.
- To investigate intensively.
- To engage in espionage.
- To seek or observe something secretly and closely.
- To make a careful investigation: spying into other people's activities.