observer

noun

ob·​serv·​er əb-ˈzər-vər 

: one that observes: such as

a

: a representative sent to observe but not participate officially in an activity (such as a meeting or war)

b

: an expert analyst and commentator in a particular field

political observers

Synonyms of observer

• spectator
• viewer

Examples of observer in a Sentence

According to one observer, the event was poorly organized.

The star is not visible to an observer without a telescope.

According to one military observer, this change comes after years of planning.

Observers say the economy is improving.

The class has an observer today, so please be on your best behavior.

Recent Examples on the Web

Mobilization speculation Some external observers have said Russian authorities appear to have been preparing the ground for a fresh wave of military mobilization after the State Duma election, a prospect that is deeply unpopular within Russia. — Sam Meredith,anniek Bao, CNBC, 17 Sep. 2026

So the guidance field for the particle can depend on very distant observers. — Quanta Magazine, 17 Sep. 2026

Those two changes mean an observer could actually see three apparent images of the spacecraft at certain moments. — Georgina Jedikovska, Interesting Engineering, 16 Sep. 2026

That scenario has leapt from the realm of science fiction into forecasts about the near future, at least among some AI employees and observers. — Max Zahn, ABC News, 16 Sep. 2026

Word History

Etymology

observe + -er entry 2

First Known Use

circa 1550, in the meaning defined above

Phrases Containing observer

• casual observer
• inter-observer

Rhymes for observer

• preserver
• fervor
• fervour
• server