1) to have more, or a greater part or share
1a) to be superior, excel, surpass, have an advantage over
2) to gain or take advantage of another, to overreach
Part of Speech: verb
Citing in TDNT: 6:266, 864
From G4123; to be covetous, that is, (by implication) to over reach: - get an advantage, defraud, make a gain.
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 πλεονεκτέω; click on the second column to search for that grammatical form of the root πλεονεκτέω; click on the third column to search for that word and grammatical form; click on the total to search for the root πλεονεκτέω.