[noun] [C]An observer is a person who watches what happens but has no active part in it.Observers of the political situation/Political observers say it's going to be a closely fought election.The conference was attended by 200 delegates and also by observers from another 30 countries.UN observers are monitoring the ceasefire.
OBSERVER
Meaning of OBSERVER in English
Cambridge English vocab. Кембриджский английский словарь. 2012