同義詞
1. work for a government or other organization by secretly obtaining information about enemies or competitors
2. observe (someone) furtively
- observe furtively
- , keep under surveillance
- , watch
- , keep a watch on
- , keep an eye on
- , keep under observation
- , follow
- , shadow
- , trail
- , tail
- , surveil
3. discern or make out, especially by careful observation
- notice
- , observe
- , see
- , spot
- , sight
- , catch sight of
- , glimpse
- , catch/get a glimpse of
- , make out
- , discern
- , pick out
- , detect
- , have sight of
- , clap/lay/set eyes on
- , espy
- , behold
- , descry