dressed-up vs dressed to the nines

dressed-up and dressed to the nines both are adjectives.

Word	Noun	Adjective	Verb	Adverb
dressed-up	No	Yes	No	No
dressed to the nines	No	Yes	No	No

As adjectives, dressed-up and dressed to the nines are synonyms defined as:

dressed-up and dressed to the nines: dressed in fancy or formal clothing

Other synonyms of dressed-up include dolled up, dressed, dressed to kill, spiffed up, spruced up, togged up.

dressed-up (adjective)	dressed to the nines (adjective)
dressed in fancy or formal clothing	dressed in fancy or formal clothing