Lewis & Short

ĭn-ēnarrābĭlis, e, adj., that cannot be related or described, indescribable (mostly post-Aug.): mira quadam et incredibili atque inenarrabili pietate, Vell. 2, 99, 2: labor, Liv. 44, 5, 1: tabes (jecoris), id. 41, 15, 2: natura fluminum, Sen. Q. N. 3, 22: ratio, Quint. 11, 3, 177: habitus, Plin. 8, 7, 7, § 21.