What the little black dress is for evening, gray flannel pants are for 9 to 5 — a wardrobe fundamental that never goes out of style. But they can look a bit severe. The key is to wear them with a soft, feminine top — a silk shirt, for example, or an oversized, off-the-shoulder sweater in cashmere or mohair — that offsets the strict tailoring of the trousers. Then complete the look with of-the-moment stilettos. This, too, is critical: A dated shoe will ruin the whole ensemble.
Here are several styles, ranging from traditional to somewhat trendy. THE CLASSICS: Santorelli’s Mara pants, in 100% wool, are super-chic and absolutely timeless. With slightly fuller legs and a high-to-mid rise, they sit almost at the waist. Mid-rise options also include Lafayette 148’s Delancy pants in stretch wool, which are unhemmed (a plus if you want to match them to a specific height of heel); and AWoman’s sleek wool pants, also blended for stretch. FASHION UPDATES: Weekend Max Mara’s Speleo stretch pants are pegged and tapered for a more modern silhouette. And Miu Mui’s cropped pants, with beautiful detailing, offer the most fashion-minded alternative. But remember, a pair of gray flannel pants can last for many seasons. Approach them as an investment piece and go for the best quality you can afford. — Lola Ehrlich and John Birmingham