#weightlessness__lightness__lightnes  the property of being comparatively small in weight; "the lightness of balsa wood"
  exclusion:  weightiness
  supertype:  weight  the vertical force exerted by a mass as a result of gravity
  subtype:  buoyancy__airiness  the property of something weightless and insubstantial

No statement uses or specializes weightlessness; click here to add one.