Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
implētĭo (inpl-), ōnis, f. [impleo], the ful filment (eccl. Lat.), Salv. Gub. 2, 2, p. 52 Rittersh.; Hier. in Isa. 11, 40, 3 sqq.