The word "nonturbulent" means calm or peaceful, so its antonyms will be words that describe conditions of turbulence or unrest. Some words that are opposite to "nonturbulent" are tumultuous, chaotic, tempestuous, stormy, unsettled, turbulent, and tricky. These antonyms imply commotion, disruption, or disorder in various areas of life, such as politics, finance, relationships, weather, or emotions. For instance, a tumultuous relationship is one that is continuously beset by conflicts, while a stormy weather indicates heavy wind, rain, and thunder. Conversely, a nonturbulent environment is one that is harmonious, placid, or tranquil, which is essential for relaxation, creativity, and well-being.