Without additional information, this appears to be a Bondeøkse. A Norwegian Battle Axe or Peasant Axe, used mostly by farmers due to a law from the 1600's.
The haft is curved because the axe was used to stab and slash, not chop.
Below is the text from that page poorly translated to English:
The Land Guard in the Norwegian Code of 1604 states that the people had a duty to guard the homeland in case of external attacks. It is clear from the law that on the basis of property and social position, the farmer should pose with ax, spear, tea bag, long-sleeve and arm-chest. The collections contain over 70 farmer axes. These were axes intended for battle, that is weapons axes or battle axes. Ax could be very effective weapons. The pointed shape of the blade allowed you to bump and stab. The ax could also be used as a hook for hooking and tearing down, for example, a horse rider. The ax blade has a curved shape and as a sable this gives a deep and effective cut. The Norwegian peasant was to defend the country against external enemies. There are therefore many such farmer axes. We know the axes from the Viking Age and the migration period. While weapon axes went out of fashion in the rest of Europe, it was still in use in Norway until about 1800. The peasant ax had lost its role in war, but was an important social symbol of the free Norwegian peasant. The ax is also a national symbol and appears in the Norwegian national arms with lion and ax.
If you don't get a response here try /r/whatisthisthing . They know a lot certainly about specialized tools.