Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
inconsīdĕrantĭa, ae, f. [inconsiderans], want of reflection, inconsiderateness (= temeritas, incuria): alicujus inconsiderantiam sustinere (where some read considerantiam), Cic. Q. Fr. 3, 9, 2: mirari inconsiderantiam (al. inconsiderationem), Suet. Claud. 39; Salv. Gub. Dei, 1, 11.