The Greek noun agnoema (ἀγνόημα) means an error, an act done in ignorance, or a sin of ignorance — something wrong done without full knowledge. It appears once in the New Testament (Hebrews 9:7) and specifically in the context of the Day of Atonement sacrifices offered for the people's sins of ignorance. The word derives from a- (not) and ginosko (G1097, to know).
The word highlights an important distinction in biblical ethics: sins committed in ignorance are treated differently from willful, deliberate sin — though both require atonement.
Hebrews 9:7 describes the high priest entering the Holy of Holies once a year to offer blood "not without blood, which he offered for himself and for the sins the people had committed in ignorance." The agnoema — sins of unknowing — were not innocent but still required atonement. The sacrificial system acknowledged that humans accumulate guilt even for what they do not fully understand they have done.
The concept connects to Paul's autobiographical reflection: "I was formerly a blasphemer and a persecutor and an insolent man, but I received mercy because I acted ignorantly in unbelief" (1 Timothy 1:13). Paul's pre-conversion zeal against Christians was a terrible agnoema — a grave sin, yet one committed in ignorance of who Jesus was. Christ's atoning sacrifice covers not only deliberate sins but the full range of human moral failure, including what we do not know we do wrong. "Forgive them, Father, for they do not know what they are doing" (Luke 23:34).