The phrase "look blue" is often used to describe someone who appears sad or depressed. However, there are many synonyms that can be used to convey a similar meaning. These include "feeling down," "feeling low," "feeling glum," "feeling dejected," and "feeling melancholy." Other words that can be used to describe a blue mood include "sorrowful," "forlorn," "gloomy," and "morose." Using a range of different words and phrases can help to convey a more nuanced and empathetic understanding of someone's emotional state, rather than relying on one overused term.