weightiness

The quality or state of being weighty; weight; force; importance; impressiveness.

noun

1. The state or quality of being physically heavy: heaviness, heftiness, massiveness, ponderosity, ponderousness, weight. Informal avoirdupois. See heavy/light.
2. The condition of being grave and of involving serious consequences: graveness, gravity, momentousness, seriousness. See important/unimportant.
3. The quality or state of being important: concern, concernment, consequence, import, importance, moment, significance, significancy, weight. See important/unimportant.

The noun has one meaning:

Meaning #1: the property of being comparatively great in weight
  Synonym: heaviness