SPY

[verb] [I]To spy is to secretly gather and report information about the activities of another country or organization.He's been held in prison for three years for alleged spying.He was arrested for spying on missile sites.To spy on someone is also to watch them in secret.I can spy on my neighbours through this window without being seen.(informal) I generally like to spy out (= obtain knowledge of) restaurants before I go to eat in them. [M]If you spy out the land you try to obtain knowledge of something in advance.We drove around the area where our new house is to spy out the land.