Definitions for vacuousness
Random House Webster's College Dictionary
vac•u•ousˈvæk yu əs(adj.)
lacking in or showing a lack of ideas or intelligence:
a vacuous mind.
Origin of vacuous:
1645–55; < L vacuus empty
indicative of or marked by mental vacuity and an absence of ideas
"the vacuousness of her face belied her feelings"
the quality of being vacuous
the quality or state of being vacuous; emptiness; vacuity