The Greek adjective akatagoostos (ἀκατάγνωστος) combines the alpha-privative with kataginosko (to find fault, condemn). It means beyond reproach, above condemnation, or not able to be condemned.
Akatagoostos appears only once in the New Testament — Titus 2:8 — in Paul's instructions to Titus about teaching sound doctrine: 'In your teaching show integrity, seriousness, and soundness of speech that cannot be condemned (akatagoooston), so that those who oppose you may be ashamed because they have nothing bad to say about us.' The Christian life is to be lived at such a moral and rhetorical level that critics are silenced by its integrity. This is the apologetic power of holy living.