This shape tell me of two different origins:
1. Throwing knife indeed, the rather large size and distal taper suggest it is an item made to an expert, possibly a circus thrower. The small hilt area is typical, the grips were usualy of thick leather or fiber, riveted through (check for example the knives made by world famous thrower/knifemaker Harry McEvoy
http://www.robertg.com/knifethrowing.htm).
2. Puntilla, Spanish bullfighting dagger, it resembles a throwing knife
http://www.loveleaf.net/ts/652.html