Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
excōgĭtātĭo, ōnis, f. [excogito], a thinking out, a contriving, devising, inventing (syn. inventio): quid? illa vis quae tandem est, quae investigat occulta, quae inventio atque excogitatio dicitur? Cic. Tusc. 1, 25, 61: excogitationem non habent difficilem, may be thought out without difficulty, id. de Or. 2, 27, 120: hominum malae artis, Vulg. Sap. 15, 4.