"Dress up" is a phrase that can be used to describe the act of putting on formal or fancy clothing. However, there are many alternative words and phrases that can be used to express this concept in different ways. Some synonyms for "dress up" include "don attire," "adorn oneself," "primp and polish," "deck out," "spruce up," and "get dolled up." Each of these phrases carries a slightly different connotation, so choosing the right one depends on the context and tone of the sentence. Whether you're getting ready for a fancy event or just trying to impress someone, there are plenty of ways to describe the act of "dressing up" to suit your needs.