There are many synonyms for the phrase "looked smug" that can be used to convey a similar meaning. Some examples include "appeared pleased with oneself," "exuded arrogance," or "wore a self-satisfied expression." Other potential phrases include "seemed conceited," "displayed haughtiness," or "had a smirking demeanor." Each of these expressions carries a slightly different nuance but all generally relate to someone feeling a sense of superiority or satisfaction with themselves. When choosing a synonym, it's important to consider the context and tone of the sentence to select the best option, so as to ensure clear and effective communication.