Scabbard
If it is a hunting type knife the answer is sheath.
A sturdy sheath will protect your sword from incidental damage. The Bowie knife, also known as an Arkansas toothpick, is a large sheath knife.
The word sheath refers to something that is meant to cover something for protection. The usual uses for a sheath would be to cover and protect the blade of a knife, sword or dagger.
A scabbard is a sheath, typically made of leather or metal, that is used to hold and protect a sword, knife, or other bladed weapon when it is not in use. It helps to prevent the blade from becoming dull or damaged and provides a safe way to carry the weapon.
In a sheath,that is what the sword case is called
a sheath
A sheath knife is a knife blade that fits in a cover of some sort of material such as nylon or leather. The cover protects the knife, and also serves as a carrier.
He may, but if he is caught with such in his possession, he could also be charged with carrying a concealed weapon (for the knife in his pocket or a sheath, and for possession of the sword as a felon carrying a weapon.
A scabbard is a sheath for holding a sword.
sword..
you cover it with a sheath
A sheath