1) one who does anything, a doer
2) one who does the work of inflicting punishment or taking vengeance
2a) the avenger of murder
2b) the exactor of a monetary fine
2c) an officer of justice of the lower order whose business it is to inflict punishment
Part of Speech: noun masculine
Citing in TDNT: 6:642, 927
From a derivative of G4238; a practiser, that is, (specifically) an official collector: - officer.
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 πράκτωρ; click on the second column to search for that grammatical form of the root πράκτωρ; click on the third column to search for that word and grammatical form; click on the total to search for the root πράκτωρ.