vas·ti·ty I. \-stəd.ē, -ətē, -i\noun (-es) Etymology: Middle French vastité, from Latin vastitat-, vastitas, from vastus empty, waste + -itat-, -itas -ity archaic: a waste or desolate condition < all the vastity of the Arabian peninsula — C.M.Doughty > II. noun (-es) Etymology: Latin vastitas, from vastus vast + -itas -ity : vastitude < the dreadful vastity of the stars — Rose Macaulay >