IPA: /ˈreɪləs/
KK: /ˈreɪləs/
Not having any rays of light or brightness; completely dark or shadowy.
The garden looked eerie under the rayless sky.
Rayless → It is formed from "ray" (from Old English "rǣge", meaning a beam of light) and "-less" (meaning without). The word "rayless" means without rays or beams of light.
Think of being 'without' ('-less') any 'beams of light' ('ray') — that's what rayless means.