1) not standing the test, not approved
1a) properly used of metals and coins
2) that which does not prove itself such as it ought
2a) unfit for, unproved, spurious, reprobate
Part of Speech: adjective
Citing in TDNT: 2:255, 181
From G1 (as a negative particle) and G1384; unapproved, that is, rejected; by implication worthless (literally or morally): - castaway, rejected, reprobate.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root ἀδόκιμος; click on the second column to search for that grammatical form of the root ἀδόκιμος; click on the third column to search for that word and grammatical form; click on the total to search for the root ἀδόκιμος.