IPA: /ˈskɑːrləs/
KK: /ˈskɑr.ləs/
Having no marks or blemishes on the skin that are left from injuries or wounds.
After the surgery, the doctor assured her that she would be scarless.
Scarless → It is formed from "scar" (from Old Norse *skarð*, meaning a notch or cut) and "-less" (meaning without). The word "scarless" means without scars or marks from cuts.
Think of being 'without' ('-less') any 'notches or cuts' ('scar') — that's why scarless means having no scars.