IPA: /ˈflæɡləs/
KK: /ˈflæɡləs/
Not having a flag attached or displayed.
The flagless ship sailed quietly into the harbor.
Flagless → It is formed from "flag" (from Old English *flæge*, meaning a piece of cloth or banner) and "-less" (meaning without). The word "flagless" means without a flag or banner.
Think of being 'without' ('-less') a 'banner' ('flag') — that's what flagless means.