A 'yes-man' refers to someone who always agrees with others, even if they disagree with them. This is a term commonly used in offices and corporate settings where people who do not provide constructive feedback are considered to be 'yes-men'. Some synonyms for 'yes-man' include sycophant, flatterer, lapdog, lackey, follower, and puppet. These words describe individuals who are subservient and are more concerned with pleasing others than expressing their own opinions. While it is important to be agreeable and considerate in a professional setting, it is equally essential to offer constructive criticism and feedback to help improve the quality of work.