An "open cardigan" refers to a type of knitted sweater that doesn't have buttons or a zipper on the front. It is open at the front, allowing it to drape over the torso without fastening. Full definition
I bought this stripe long open cardigan thinking it would be perfect for post baby. (pinkandnavystripes.com)
I promise you though, you'll be grabbing this cozy open cardigan every time you're ready to walk out the door, it's that soft and comfortable! (thestyledfox.com)
You can look perfect while wearing these along with a front open cardigan. (outfittrends.com)