The Ork Choppa is the default melee weapon of Orks.
The weapon, like all of Ork craft, is of crude design. It consists of a blade of some sort, sharpened by stone as opposed to being intricately smithed. The end product is a weapon that mimics an axe or a large knife.
In Dark Millennium Online Edit
Orks have been seen wielding the weapon in the original game trailers.