observer
US /əbˈzɝː.vɚ/
UK /əbˈzɝː.vɚ/

1.
2.
observador
a person who attends a meeting or event without participating in it
:
•
She attended the conference as an observer, not a speaker.
Asistió a la conferencia como observadora, no como oradora.
•
International observers were present during the elections.
Observadores internacionales estuvieron presentes durante las elecciones.