The Collaborative International Dictionary of English v.0.48:

Gentilitial \Gen`ti*li"tial\, Gentilitious \Gen`ti*li"tious\, a.
   [L. gentilitius. See Gentile.] [Obs.]
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   1. Peculiar to a people; national. --Sir T. Browne.
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   2. Hereditary; entailed on a family. --Arbuthnot.
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