A zombie villager is a variant of the zombie that can be cured into a normal villager using a golden apple while it is under the effect of Weakness. https://minecraft.fandom.com/wiki/Zombie_Villager
Weakness can be applied by:
- A splash potion of Weakness thrown by the player, a dispenser, or a witch.
- An area effect cloud of Weakness from a lingering potion.
- An area effect cloud of Weakness from a creeper explosion.[Java Edition only]
- A tipped arrow.
- A command (/effect @e[type=zombie_villager] weakness)
If successful, a loud sizzling sound is heard and the zombie villager begins to shudder. The curing process takes 3–5 minutes, during which time the zombie villager behaves like a normal zombie. The zombie villager gains Strength while converting. The potency of the effect isn’t affected by difficulty. This would mean that zombie villagers being cured are more dangerous than regular zombie villagers.