1) that which has not only the name and resemblance, but the real nature corresponding to the name, in every respect corresponding to the idea signified by the name, real, true genuine
1a) opposite to what is fictitious, counterfeit, imaginary, simulated or pretended
1b) it contrasts realities with their semblances
1c) opposite to what is imperfect defective, frail, uncertain
2) true, veracious, sincere
Part of Speech: adjective
Citing in TDNT: 1:249, 37
From G227; truthful: - true.
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 ἀληθινός; click on the second column to search for that grammatical form of the root ἀληθινός; click on the third column to search for that word and grammatical form; click on the total to search for the root ἀληθινός.