IPA: /ˈlaɪn.ləs/
KK: /ˈlaɪn.ləs/
Having no lines or markings on a surface.
The artist created a lineless design that emphasized simplicity.
Lineless → It is formed from "line" (from Old English "line", meaning a straight mark or stroke) and "-less" (meaning without). The word "lineless" means without lines or markings.
Think of something that is 'without' ('-less') any 'lines' — that's what lineless means.