WordWeb Online

1. A person employed to keep watch for some anticipated event
   - lookout, lookout man, sentinel, sentry, watch, scout, picket
    
2. [Brit] Someone who observes or takes notes about instances of a particular type of thing as a hobby
   "train spotters"; "bird spotter"
    
3. A worker employed at a dry-cleaning establishment to remove spots
    
4. A worker employed to apply spots (as markers or identifiers)
    
5. Someone who is the first to observe something
   - finder, discoverer

Derived forms: spotters

Type of: beholder, employe [US], employee, observer, perceiver, percipient, security guard, watcher, watchman

Encyclopedia: Spotter