IPA: /ˈliːfləs/
KK: /ˈlifləs/
Describing a plant or tree that does not have any leaves.
In winter, many trees become leafless as they shed their leaves.
Leafless → It is formed from "leaf" (from Old English *leaf*, meaning the foliage of a plant) and "-less" (meaning without). The word "leafless" describes a state of being without leaves.
Think of a plant that is 'without' ('-less') its 'foliage' ('leaf') — that's what leafless means.