A casual blazer typically features a solid color and a more structured silhouette, often with metallic buttons and minimal patterning, making it slightly dressier. A sport coat, on the other hand, is generally more relaxed in fit and style, often showcasing patterns like checks or plaids, textured fabrics, and details inspired by outdoor or sporting activities. Both are versatile, but sport coats tend to offer more variety in fabric and design, lending themselves well to informal and smart-casual occasions.