SPY

Definition

1. noun (military) a secret agent hired by a state to obtain information about its enemies or by a business to obtain industrial secrets from competitors. — synonyms: undercover_agent
2. noun a secret watcher.
3. verb catch sight of. — synonyms: descry, spot, espy
4. verb watch, observe, or inquire secretly. — synonyms: stag, snoop, sleuth
5. verb catch sight of. — synonyms: sight
6. verb secretly collect sensitive or classified information.