noun
keeping a secret or furtive watch
noun
the act of keeping a secret watch for intelligence purposes
Synonyms
undercover work
noun
the act of detecting something
Synonyms
Examples
- catching sight of something
verb
catch sight of
Synonyms
verb
watch, observe, or inquire secretly
Synonyms
verb
catch sight of
Synonyms
Examples
- to perceive with the eyes
- he caught sight of the king's men coming over the ridge
verb
secretly collect sensitive or classified information
Synonyms
Examples
- engage in espionage
- spy for the Russians