Can Men Wear Sweatpants to a Fancy Party Now?

Work-from-anywhere lifestyles have inspired ‘elevated lounge pants’ that crossbreed sweats and dress slacks. But how far outside your living room can they go?

ARE YOU wearing pajamas?” asked my friend at a bar last Sunday. “They’re...wool sweatpants,” I said uncertainly. I didn’t actually know what to call the Barena pants I had on. With an elastic waist and fine wool fabric, they weren’t sweatpants, but they weren’t not sweatpants. They were the pant version of a Labradoodle, a status mutt. They were also the most comfortable pants I’d ever worn.

The world of men’s trousers has been, as the Silicon Valley folks say, “disrupted.” Designers are playing Dr. Frankenstein, combining...