Related Definitions
[n] a secret agent hired by a state to obtain (military) information about its enemies or by a business to obtain industrial secrets from competitors
[n] a secret watcher; someone who secretly watches other people; "my spies tell me that you had a good time last night"
[v] secretly collect sensitive or classified information; engage in espionage; "spy for the Russians"
[v] watch, observe, or inquire secretly
[v] catch sight of