Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
adjūrātĭo, ōnis, f. [adjuro], a swearing to something by something, swearing, adjuration: adjuratione suae salutis, by swearing by her own safety, App. M. 2, p. 123 fin.: divini nominis, Lact. 2, 17.