Definition of insecure. 1  1 : not confident or sure : uncertain feeling somewhat insecure of his reception. 2  2 : not adequately guarded or sustained : unsafe an insecure investment. 3  3 : not firmly fastened or fixed : shaky the hinge is loose and insecure.
For men, semi-formal attire means wearing a full suit, with vest optional. A tie, either bow or straight, should be worn, and the shirt should be a simple button down. Suit fabric choices are primarily wool gabardine or cashmere. However, a wool blend will do.
Women's Semi-Formal Dress. For women, a semi-formal dress code dictates party-appropriate attire, but it does not require an evening gown. Shorter, knee-length cocktail dresses and classic little black dresses accessorized with heels and jewelry are good choices for semi-formal events.