dress up vs adorn

dress up and adorn both are verbs.

Word	Noun	Adjective	Verb	Adverb
dress up	No	No	Yes	No
adorn	No	No	Yes	No

As verbs, adorn is a hypernym of dress up; that is, adorn is a word with a broader meaning than dress up:

Other hypernyms of dress up include beautify, decorate, embellish, grace, ornament.

dress up (verb)	adorn (verb)
put on special clothes to appear particularly appealing and attractive	make more attractive by adding ornament, colour, etc.
dress in a costume	furnish with power or authority; of kings or emperors
dress in a certain manner	be beautiful to look at
make something appear superficially attractive
put a caparison on