n.
1.(military) a secret agent hired by a state to obtain information about its enemies or by a business to obtain industrial secrets from competitors
2.a secret watcher spy v.
1.catch sight of
2.watch, observe, or inquire secretly
3.secretly collect sensitive or classified information
Idiom of the Day
a known quantity
someone or something that is known and understood
The new employee is a known quantity in our office because he worked here before.