someone who is good at noticing or finding something

As a spotter of current and emergent trends, he has few competitors. 作为当前和新兴趋势的观察者，他几乎没有竞争对手。

She's a great talent spotter.

someone who watches a place, looking for someone or something, especially in order to warn people

Organized racers have become harder to catch, with spectators monitoring police radios and spotters posted down the road watching for patrol cars. 有组织的飙车手变得更难抓到，观众会监听警察的无线电，观察员会被安插在路上以监视警车。

someone who works on a building site (= an area of land where something is being built) whose job is to make sure that vehicles and heavy machinery are used correctly and safely

Using spotters to control traffic is common, according to a Maryland construction safety consultant. 据马里兰州建筑安全顾问称，使用安全员调度交通很常见。

someone who watches weather patterns, especially as a job

Together with other chasers and spotters, he can assess the storm from every angle. 他可以与其他气象追踪者和观测者一起，从各个角度评估风暴。

Tornado warnings in the U. S. are issued when twisters are witnessed by spotters or signs are detected by radar.

in weight training and gymnastics, someone who stands next to the person lifting weights or doing particular movements in order to make sure they do not injure themselves

All he does in the gym is stand around and talk to his spotter. 他在健身房里就只是站在那儿和陪练员说话。

used to refer to a person whose job or interest is to notice people or things of the type mentioned

a talent-spotter 星探

UK a train-spotter 因为兴趣而搜集铁路机车号码的人