Can’t tell you about the authenticity of this piece, or how old it is, but here is what I see in the inscription:
The dot makes the whole difference.
With out it the word reads Hazeen, as Mr.AlAnizi indicated. But after some search, I found out that it is a dot and part of the word, and not just a dent.
The word with the dot reads Jezzin, which is an area in south Lebanon, famous for making such khanjars.
Sources:
http://www.aawsat.com/details.asp?se...508&issue=9388
http://www.lebanon.com/tourism/jezzin.htm