Semi-formal events are a bit less formal than formal events but not as relaxed as smart casual. For men, this could mean wearing a suit with no tie, or even a sports coat. A dress shirt and trousers are also an option. For women, semi-formal attire usually means wearing a dress or pantsuit. skirts and dresses should be knee-length or longer, and you should avoid very flashy or revealing outfits. A cocktail dress is perfect for a more formal wedding, but it can also be worn to other semi-formal events. For women, a cocktail dress should be knee-length or shorter and have straps or be sleeveless. It’s also important to avoid too much skin exposure. You don’t want to wear something that’s too sexy or revealing. When it comes to color, stick to darker shades like navy, black, and purple.