What is Downless?

Downless definition and meaning on Dictionary terms:
the soft, first plumage of many young birds.
the soft under plumage of birds as distinct from the contour feathers.
the under plumage of some birds, as geese and ducks, used for filling in quilts, clothing, etc., chiefly for warmth.
a growth of soft, fine hair or the like.
Botany. a fine, soft pubescence on plants and some fruits. the light, feathery pappus or coma on seeds by which they are borne on the wind, as on the dandelion and thistle.

filled with down: a down jacket.