1. (

• spying ,

) keeping a secret or furtive watch ;

2. (

• spying ,
• undercover_work

) the act of keeping a secret watch for intelligence purposes ;

3. (

• detection ,
• catching ,
• espial ,
• spying ,
• spotting

) the act of detecting something; catching sight of something ;

1. (

• descry ,
• spot ,
• espy ,
• spy

) catch sight of ;

2. (

• spy ,
• stag ,
• snoop ,
• sleuth

) watch, observe, or inquire secretly ;

3. (

• spy ,
• sight

) catch sight of; to perceive with the eyes; "he caught sight of the king's men coming over the ridge" ;

4. (

• spy

) secretly collect sensitive or classified information; engage in espionage; "spy for the Russians" ;