remark vs observe

remark is a noun but observe is not a noun.

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

As verbs, remark and observe are synonyms defined as:

Other synonyms of remark include mention, note.

As verbs, observe is a hypernym of remark; that is, observe is a word with a broader meaning than remark:

Other hypernyms of remark include mention, note, remark.

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

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