The athletic games of Paul's times were exciting, popular, and exacting. No cheating or breach of the rules was allowed. The judges stood at strategic spots to observe and monitor the actions of athletes in the sporting contests. If any Olympic athlete crossed the line of fairness, a referees or umpire would point and cry out, “Adokimos!"
Every two years the Corinthians people enjoyed the Isthmian games, and so when Paul wrote about the disqualiification of a Christian's effectiveness due to sin, the reader knew exactly what he was talking about. The word meant to be put to the test...and to fail. The context of Paul's writing seems to tell us that fleshly sins will disqualify us from a power in teaching and handling the Gospel to share to others.
May we never be adokimos!