A spectator; someone looks on or watches, without becoming involved or participating.

plural of onlooker

simple past tense and past participle of onlook

That is looking on; watching, observing.

The act of looking on (something); observation. / That which is looked at, regarded, or considered. / (rare) One's perspective or outlook.

(intransitive) To look on or look at; watch; observe; view; regard.

plural of onlook