A blazer is a type of jacket resembling a suit jacket but cut more casually. It is typically a standalone piece of clothing, not part of a matching suit, and is often made from durable fabrics like wool, flannel, serge, or linen. Versatility: One of its defining features is its adaptability. Blazers can be dressed up or down, making them suitable for a wide range of occasions, from business casual to smart casual, and even semi-formal events.