IPA: /ˈsaɪt.ləs.li/
KK: /ˈsaɪt.ləs.li/
In a way that does not involve sight; without seeing.
She moved sightlessly through the dark room, relying on her other senses.
Sightlessly → It is formed from "sight" (from Old English *sīht*, meaning the ability to see) and the suffix "-less" (meaning without). The word "sightlessly" means without the ability to see or lacking sight.
Think of 'sight' as the ability to see, and '-less' means without. So, sightlessly helps you remember that it refers to being without sight.