Reprobate describes what is rejected because it is worthless or has failed a test. The term may describe persons who have failed to use their opportunities or who have not proved genuine in faith and good works. It can also describe land that, instead of producing useful growth, bears thorns and thistles.
In biblical usage, reprobate retains the idea of rejection because of failure under trial. It is applied to people who disappoint the expectation of good works and to land that fails the husbandman’s test by producing thorns.
The term reflects the contrast between what is approved after testing and what is found wanting. Its underlying biblical usage therefore combines testing, approval or disapproval, and consequent rejection.