The Greek adjective amiantos (ἀμίαντος) combines the alpha-privative with miainoo (to stain, defile). It means undefiled, pure, unstained, or without contamination.
Amiantos appears in three key New Testament passages. Hebrews 7:26 describes Christ as 'holy, blameless, pure (amiantos), set apart from sinners' — his qualifications as the eternal high priest. Hebrews 13:4 declares marriage 'honorable among all' and the marriage bed 'undefiled (amiantos).' James 1:27 defines pure religion as 'undefiled (amiantos) before God.' In each case, amiantos marks the standard of covenant purity — whether of Christ's person, marriage, or true worship.