After-five attire is another term for semi-formal attire, which includes dark suits for men and cocktail dresses for women. When after-five attire is specified for an afternoon event, lighter suits for men and dressy separates for women are acceptable.
According to Real Simple Magazine, after-five attire is best for most weddings, fund raisers and semi-formal parties when no other clothing clues are given on the invitations or by the hostess. A classic little black dress is always appropriate for a woman. Modest hemlines and minimal décolletage are best, and an upscale feel wins out against showiness. Men look great in classic black or other dark suits with white shirts and dark ties.