"Doll up" means to dress up or make oneself look more attractive. Its antonyms would be words that imply simplifying or downplaying one's appearance. Some possible antonyms for "doll up" could include "dumb down," "dress down," "tone down," "simplify," "neglect," or "disregard." These words could suggest a lack of effort or interest in one's appearance, or a deliberate choice to present oneself in a more natural or casual way. While "doll up" is often associated with femininity and glamour, its antonyms can carry a more androgynous or laid-back vibe.