Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
innŭmĕrābĭlĭtas, ātis, f. [innumerabilis], countless number, innumerableness: mundorum, Cic. N. D. 1, 26, 73: atomorum, id. ib. 1, 39, 109; Arn. 3, p. 132 Herald.