"Play the shrinking violet" means to act shy or hesitant to draw attention to oneself. Some synonyms for this phrase include acting reserved, being demure, or behaving timidly. Other expressions with similar meanings include being a wallflower, fly on the wall, or a mouse in the corner. These phrases all convey the idea of being passive or unassuming in social situations. However, it is important to note that there is strength in being quiet and reserved. People who are introverted or shy may have a unique perspective or talent that can benefit the world. So, it's okay to be a shrinking violet sometimes.