To make a eunuch, either literally (castration) or figuratively (voluntary celibacy for the sake of God's kingdom). Jesus uses this word in one of His most startling teachings — that some choose to live as eunuchs for the kingdom of heaven, and this is a valid, honored calling.
Eunouchizo in Matthew 19:12 is one of Jesus's most radical statements on discipleship. He acknowledges three categories: those born eunuchs, those made eunuchs by others, and those who choose celibacy for the kingdom. This validates singleness as a high calling — not a deficiency but a charisma (gift). Paul elaborates in 1 Corinthians 7: the unmarried person can give 'undivided devotion to the Lord.' The word destroys the false hierarchy that marriage is superior to singleness.