Minecraft wiki entry for Best_enchantments_guide, associated text: The following sword/axe enchantments cannot be combined: Sharpness, Smite, and Bane of Arthropods. Depending on what you want to do with the sword or axe, you can choose the most suitable. Sharpness is useful for general use, Smite is useful against undead mobs (skeletons, zombies, withers, etc.), Bane of Arthropods is useful against Arthropods (spiders, cave spiders, bees, silverfish, and endermites). Each level of Smite and Bane of Arthropods deals 2.5 extra damage to the specific group of mobs. Sharpness deals 1.25 extra damage [Bedrock Edition] and 0.5 * level + 0.5 extra damage in Java Edition. If you are going to battle a lot of undead mobs (with the same sword or axe) more than every third[Bedrock Edition / fourth[Java Edition, level I to II] / fifth[Java Edition, level III to V] time, Smite deals the most damage. The same rule is not fully valid for choosing Bane of Arthropods, as Arthropods have low health, meaning Sharpness should be enough. Sharpness is the best choice, so have another sword with Smite for zombie farming (optional), or carry both a sharpness sword and a smite sword (optional, only if you have good inventory management).