Webster’s Revised Unabridged Dictionary · 1913
Observer
Ob·serv′er, 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. "Diligent observers of old customs." Spenser.
These . . . hearkend unto observers of times. Deut. xviii. 14.
3. One who fulfills or performs; as, an observer of his promises.
4. A sycophantic follower. [Obs.] Beau. & Fl.