The Collaborative International Dictionary of English v.0.48:

Exteriority \Ex*te`ri*or"i*ty\, n. [Cf. F. ext['e]riorit['e].]
   Surface; superficies; externality.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

18 Moby Thesaurus words for "exteriority":
   cursoriness, epidermis, gloss, mere scratch, no depth, no water,
   pinprick, rind, scratch, shallowness, shoaliness, skin, slightness,
   superficiality, superficies, surface, triviality, veneer