There’s nothing odd about odd vests! The phrase simply refers to wearing a vest outside of a three-piece-suit ensemble—a great strategy for adding visual appeal and stretching your clothing budget by increasing the number of mix-and-match options in your wardrobe.
Light-colored vests, such as sand or dove gray, look fantastic under a suit. You may choose to build your vest of the same material as your trousers or sport jacket, or instead select a coordinating fabric. The back of the vest is often constructed of thin lining fabrics to avoid adding bulk and heat. Wearing matching trousers and vest with a contrasting coat makes a striking ensemble.
The vest should be long enough to cover your waistband. Braces are a good choice with a vest, as a belt will push the vest fabric away from your waist, creating the appearance of thickness. The armholes of your vest should be large, to allow for ease of movement.