solemnise vs observe

solemnise and observe both are verbs.

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

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

Other hypernyms of solemnise include celebrate, keep.

solemnise (verb)	observe (verb)
make solemn and grave	stick to correctly or closely
observe or perform with dignity or gravity	make mention of
perform (the wedding ceremony) with proper ceremonies	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