The word smooth-spoken can be described as someone who speaks in a pleasing and charming manner. The opposite of this would be someone who is rough-spoken or has a gruff voice. This person may come across as unrefined or lacking in social graces. Other antonyms for smooth-spoken could include blunt, brusque, curt, or tactless. These individuals tend to speak their mind directly and without sugar-coating the truth. Another antonym for smooth-spoken could be inexperienced, as someone who lacks the ability or knowledge to articulate their thoughts smoothly. Overall, the antonyms for smooth-spoken are words that describe communication that is abrupt, unpolished, or unskilled.