sheathe
To slide a sword or knife back into its cover.
To sheathe a sword or knife means to slide it back into its protective cover, called a sheath. When a knight finishes a duel, he sheathes his sword by carefully returning it to the leather or metal case at his side. The sheath protects both the blade and the person carrying it, preventing accidental cuts.
Think of it like putting a pen back in its cap or sliding your phone into a case, except with something much sharper. A samurai sheathes his katana with a precise, practiced motion. A hiker sheathes her hunting knife after using it to cut rope at camp.
You might also hear people use sheathe figuratively, like when someone “sheathes their criticism” by holding back harsh words they were about to say. This suggests putting away something sharp or dangerous, choosing peace instead of conflict.
The opposite of sheathe is draw or unsheathe, which means pulling a weapon out of its sheath, ready for use.