observe vs remark

observe is not a noun while remark is a noun.

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

As verbs, observe and remark are synonyms defined as:

Other synonyms of observe include mention, note.

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

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

observe (noun)	remark (noun)
	explicit notice
	a statement that expresses a personal opinion or belief or adds information

observe (verb)	remark (verb)
stick to correctly or closely	make mention of
make mention of	make or write a comment on
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