And even as they did not like to retain God in their knowledge, God gave them over to a reprobate mind, to do those things which are not convenient; Romans 1:28
The word "adokimos" is translated ''reprobate" (Rom. 1:28; 2 Cor. 13:5-7, 2 Tim. 3:8; Tit. 1:16), "castaway" (1 Cor. 9:27), and “rejected" (Heb. 6:8). It is used to describe a counterfeit coin, deficient as to weight or quality of metal.
It is also used, figuratively, to describe a cowardly soldier who fails the test of battle; a candidate rejected for office; and a stone rejected by the builders. In each case, that which is "reprobate" has promised something by its outward appearance which it cannot deliver!
Booker, George., By The Way, ChristadelphianBooksOnline, Section IV