Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
obsignātĭo, ōnis, f. [obsigno], a sealing, sealing up (post-class.): testamenti, Paul. Sent. 4, 6, 1 sq.: tabularum, Gell. 14, 2, 7; Arn. 2, 81.
Trop. (eccl. Lat.), Tert. Bapt. 13.