(of a garment) made with a deep pleat starting at the back waistline or belt and extending up to the shoulder on each side, to avoid constriction when the wearer's arms are extended.
a garment made with such pleats at the back, especially a jacket.
Origin of bi-swing
First recorded in 1965–70
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019