Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† mysta or mystes, ae, m., = μύστης, a priest of the secret rites of divine worship, a priest of the mysteries, Ov. F. 4, 536; Aus. Idyll. 1, 2; Inscr. Orell. 2362.