1) one who with his own hands kills another or himself
2) one who acts on his own authority, autocratic
3) an absolute master
4) to govern, exercise dominion over one
Part of Speech: verb
From a compound of G846 and ἕντης hentês (obsolete; a worker); to act of oneself, that is, (figuratively) dominate: - usurp authority over.
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 αὐθεντέω; click on the second column to search for that grammatical form of the root αὐθεντέω; click on the third column to search for that word and grammatical form; click on the total to search for the root αὐθεντέω.