sentry

Từ điển WordNet v3.1 - WordNet Dictionary

noun

a person employed to keep watch for some anticipated event (Freq. 1)
• Syn:
lookout, lookout man, sentinel, watch, spotter,
scout, picket
• Derivationally related forms:
spot (for: spotter), watch (for: watch), look out (for: lookout)
• Hypernyms:
watchman, watcher, security guard

• Từ đồng nghĩa / Synonyms:
  lookout, lookout man, sentinel, watch, spotter, scout, picket