Observer

n.	1.	One who observes, or pays attention to, anything; especially, one engaged in, or trained to habits of, close and exact observation; as, an astronomical observer. The observed of all observers. - Shak. Careful observers may foretell the hour, By sure prognostic, when to dread a shower. - Swift.
	2.	One who keeps any law, custom, regulation, rite, etc.; one who conforms to anything in practice. These . . . hearkened unto observers of times. - Deut. xviii. 14.
	3.	One who fulfills or performs; as, an observer of his promises.
	4.	A sycophantic follower.

Noun	1.	observer - a person who becomes aware (of things or events) through the senses Synonyms: beholder, perceiver
	2.	observer - an expert who observes and comments on something Synonyms: commentator

TV-viewer, ace, air force, beholder, bird-watcher, bomber pilot, combat pilot, drugstore cowboy, examinant, eyewitness, fighter pilot, flyboy, gaper, gazer, gazer-on, girl-watcher, goggler, inspector, investigator, kibitzer, looker, looker-on, military pilot, naval pilot, ogler, onlooker, perceiver, percipient, scrutineer, seer, sidewalk superintendent, spectatress, spectatrix, suicide pilot, televiewer, television-viewer, tester, video-gazer, viewer, visitator, visitor, watcher