observe vs observer

observe is not a noun while observer is a noun.

Word	Noun	Adjective	Verb	Adverb
observe	No	No	Yes	No
observer	Yes	No	No	No

observe (noun)	observer (noun)
	a person who becomes aware (of things or events) through the senses
	an expert who observes and comments on something

observe (verb)	observer (verb)
stick to correctly or closely
make mention of
watch attentively
observe with care or pay close attention to
discover or determine the existence, presence, or fact of by perception with the eyes
follow with the eyes or the mind
show respect towards
behave as expected during of holidays or rites
conform one's action or practice to