observe vs notice

observe is not a noun while notice is a noun.

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

As verbs, notice is a hyponym of observe; that is, notice is a word with a more specific, narrower meaning than observe:

Other hyponyms of observe include comment, point out, remark.

As verbs, observe and notice are synonyms defined as:

observe and notice: discover or determine the existence, presence, or fact of by perception with the eyes

Other synonyms of observe include detect, discover, find.

observe (noun)	notice (noun)
	the act of noticing or paying attention
	polite or favorable attention
	a sign posted in a public place as an advertisement
	an announcement containing information about an event
	a request for payment
	advance notification (usually written) of the intention to withdraw from an arrangement of contract
	a short critical review

observe (verb)	notice (verb)
stick to correctly or closely	make or write a comment on
make mention of	express recognition of the presence or existence of, or acquaintance with
watch attentively	notice or perceive
observe with care or pay close attention to	discover or determine the existence, presence, or fact of by perception with the eyes
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