not capable of being precisely or readily described; not easily put into words
<adj.all> an indefinable feeling of terror an abstract concept that seems indefinable
defying expression or description
<adj.all> indefinable yearnings indescribable beauty ineffable ecstasy inexpressible anguish unspeakable happiness unutterable contempt a thing of untellable splendor
Indefinable \In`de*fin"a*ble\, a. Incapable of being defined or described; inexplicable. --Bp. Reynolds.
Yet somehow they have the incredible brass to suggest that some other people's children should be forced to stay in the public schools as a sacrifice to some sort of indefinable larger good that they themselves have no interest in directly supporting.