An entry taken from Lexicon Ambrosianum (Ambrosianus B12 sup. 51 and Laurentianus 59,16 fol.187r).
The headword is the perfect active participle, in the masculine nominative plural, of the verb ἁγνίζω -- a verb frequently used in the imperial and Byzantine periods and also, sporadically, in classical age. This perfect participle comes from the New Testament, 1 Peter 22 (web address 1 below); all the other occurrences of it are quotations of this one.
[1] The headword verb is glossed by the aorist participle of καθαίρω . (A Cyrilian gloss of Hesychius, Lexicon eta78, has καθαρισαντες , from καθαρίζω , with an analogous meaning.)