IPA: /ˈnoʊt.ləs/
KK: /ˈnoʊt.ləs/
Something that does not attract attention or is not easily seen or recognized.
The noteless background allowed the main subject to stand out in the photograph.
Noteless → It is formed from "note" (from Old French *note*, meaning a brief record or annotation) and "-less" (meaning without). The word "noteless" means without notes or annotations.
Think of being 'without' ('-less') any 'notes' — that's what noteless means.