A Trefoil hoodie is a hooded sweatshirt that features the classic adidas Trefoil logo. adidas hoodies can be pullover styles or zip up the front, and they often include ribbing on the cuffs and hem for a snug, cozy feel. With the mark of the iconic Trefoil, the casual silhouette gets leveled up. The hoodies also generally have pockets to stash your stuff or keep your hands warm.