What does windless mean in the following sentence? the sailboat was unable to travel very far on the windless day. without wind away from wind full of wind in a windy way

I am not exactly sure but i belive it means without wind because using context clues unable to travel very far shows that it was not windy.

on my last

"the sandy walls seemed to collapse in on themselves"

and

"the bloodshot waters seemed to have no bottom"