sentinel

名词 sentinel:

1. a person employed to watch for something to happen
   同义词：lookout, lookout man, sentry, watch, spotter, scout, picket

1. A lady in full feather approached the sentinel on the sward.
   一个衣着华丽的女人走近了草地上的哨兵。
2. One who protects, keeps watch, or acts as a sentinel.
   警卫象哨兵一样工作的人，守护，看守的人
3. The press is a sentinel of our liberty.
   新闻界是捍卫我们自由的卫兵。