dress up (Verb) — Put on special clothes to appear particularly appealing and attractive. ex. "She never dresses up, even when she goes to the opera"
dress up (Verb) — Make something appear superficially attractive. ex. "Don't try to dress up the unpleasant truth" ex. "The researcher tried to dress up the uninteresting data"
dress up (Verb) — Put a caparison on. ex. "dress up the horses for the festive occasion"
dress up (Verb) — Dress in a costume. ex. "We dressed up for Halloween as pumpkins"
dress up (Verb) — Wear clothes in a certain manner or of a certain style. ex. "he dressed up in a suit and tie"