A double-breasted suit is more formal than a single-breasted one.
Ministers of a certain persuasion often seem to have a predilection for double-breasted suits, as well as three-piece ones.
I would love to wear my double-breasted white linen suit to a party.
He would do well to expunge every double-breasted suit from his wardrobe.
Then she purred, “John, if you wear a double-breasted jacket, you must always keep it buttoned.”
He's wearin' a double-breasted blue coat and a sort of yachtin' cap.
Single-breasted waistcoats are smarter than double-breasted.
It is so arranged in front that it can be worn either with a shirt or over a double-breasted vest of cloth or leather.
"It's one of the double-breasted Keys," the thin man replied.
He had donned a double-breasted coat with brass buttons and a cap with a badge and gold cord on it.