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.
Semi-formal or informal. Getty/Jamie McCarthy. You might be relieved to know that semi-formal is not a synonym for black-tie; the two dress codes are completely separate. For semi-formal, all you need is a dark colored suit with a dress shirt and tie. Nothing too fancy is required, but the rules are a little more restrictive than business dress.