underjacket

Underjacket is a descriptive term for a garment worn under a jacket. It is not a formal category in most wardrobes but is used to describe a range of light to mid-weight tops designed to be worn beneath an outer jacket. In fashion, an underjacket may function as a layering piece that adds warmth without adding bulk, often crafted as a close-fitting knit or fleece. Materials and construction vary, with common fabrics including cotton jersey, merino wool, fleece, and synthetic blends such as polyester or nylon. Some underjackets borrow features from base layers, such as flatlock seams or moisture-wicking properties, to enhance comfort during movement.

Uses vary from outdoor layering in cold weather to casual or office wear where additional warmth is desired under a blazer or coat. Performance variants prioritize warmth, breathability, and compression, while fashion-oriented pieces emphasize sleek lines and minimal bulk.

Fit and styling emphasize a smooth silhouette beneath the outer garment. The length typically ends at the hip or slightly longer, and sleeves are cut to avoid bunching under a jacket. Colors tend to be neutral to maximize compatibility with other layers.

Care and maintenance follow fabric guidelines; merino and technical fabrics may require specific washing instructions to preserve performance. In general, machine washing cold, avoiding fabric softeners for technical fibers, and air drying or tumble drying on low is recommended.