The cocktail dress code is a slightly more casual dress code than the dark suit. This dress code is often used for casual events, such as birthday parties, pre christmas parties or cocktail parties that start after 6 p.m. For men, a stylish loose jacket and neat bottoms are the perfect outfit for a cocktail party. For women a classic cocktail dress, blazer and trousers set, or a festive skirt and top are a suitable choices.