In Dressing the Man, Alan Flusser defines drape as:
The manner in which a garment hangs from the shoulder or waist. For example, the English drape (or English lounge) is an intended style feature of men’s jackets or outercoats pioneered in the early 1920s by the Prince of Wales’s maverick tailor Frederick Scholte, inspired by the guards coat; it is characterized by fullness across the chest and over the shoulder blades to form flat vertical wrinkles for form, comfort, and the impression of muscularity. The draped silhouette dominated men’s tailored fashions throughout the 1920s and 1930s.
The classic drape cut has large, padded shoulders and a nipped waist, to emphasise and build upon a man’s V-shaped torso. Drape has the intention to make a man look stronger. Sean Connery’s Anthony Sinclair suit jackets were cut with a mild amount of drape, though his jackets do not have the built-up shoulders of the classic drape suit. Though Cyril Castle made some of Roger Moore’s suits in The Saint with a draped chest, the drape was mostly absent from his James Bond suits. The extra chest fullness practically serves James Bond, by not only offering extra ease in movement but also better concealing his PPK.
Even though the chest is larger than usual, it doesn’t mean the suit is a size larger. Very few tailors still do a drape cut, and even Anderson & Sheppard who was once known for their drape now mostly cuts a trim, clean chest. Drape has a markedly old-fashioned look that isn’t in line with today’s trim fashions. Still, English tailors use drape in the most basic definition of the term: they allow the cloth to hang from—but also conform to—the body, rather than cling to it.