windowless

From Middle English wyndowles, equivalent to window +‎ -less.

windowless (not comparable)

Having no windows, especially no external windows.
- 2021 November 2, Ramishah Maruf, “Here’s what it’s like to live in one of Charlie Munger’s windowless dorms”, in CNN Business‎:
  Billionaire Charlie Munger’s controversial plans for a massive, windowless dorm at the University of California, Santa Barbara has left many wondering – how is this even possible?
- 2022 March 23, “Stop & Examine”, in RAIL, number 953, page 71:
  "There are windowless seats / wheelchair spaces at each end of the coach where the (exterior) sliding door slides between the exterior skin and the interior trim. [...] "My photo is in coach G, the Standard buffet coach, where there's an even longer windowless section."

having no windows, especially no external windows