Blunt arrows are cheap, heavy arrows made for hunting smaller animals in order to avoid damaging their hides. As their name implies, they inflict moderate amounts of low impact blunt damage, making them a poor choice for combat or hunting larger animals but are still capable of killing if one is cruel enough to try.
With a powerful enough bow, high quality blunt arrows can potentially inflict crushing wounds.
They can be crafted by the player with a branch, tying equipment, and 3 feathers. They can also sometimes be found by trading.