Lewis & Short

ĭnaequābĭlĭtas, ātis, f. [inaequabilis],

  1. I. inequality, unlikeness, variety (postclass. and very rare), Varr. L. L. 8, 3, 108: elementorum, Arn. 2, 81.
  2. II. Gramm. t. t., = ἀνωμαλία, want of uniformity, anomaly: sermonis, Varr. L. L. 9, 1, 1.