Boden is always a good place to hunt for machine washable workwear, and this pretty wrap dress is even on sale. The neckline is low enough that I’d wear a camisole with it, as well as probably some Skimmies underneath for modesty (if not a full slip). The dress was $128, but is now marked to $76-$89 depending on size and color. Boden Summer Wrap Dress
Here’s a plus-size option.