Mat 25:46 And these shall go away into everlasting punishment: but the righteous into life eternal.
Alternative: And these will go away into the correction of ages but the virtuous into the life of ages.

As we usually see, the Greek is not nearly as damning as the English. The term for "eternal" is ambiguous, referring either to the end of an age or to something everlasting.

What is particularly interesting is the term translated as "punishment," which means literally "pruning." In the context of the theme of productivity, which is the focus of this chapter, the term is well chosen. Trees (like fields) are Christ's symbols for the productivity of wealth. The pruning is either to burn away the character flaw in the soul or to eliminate the unproductive souls from society. I choose to think both ideas are intended.

I have noted before that there are indications that Christ is subtly teaching reincarnation (John the Baptist was Elijah come again.), Read in that context, the ideas here make more sense that the Christian idea of eternal punishment or pleasure.

"Go away" is from aperchomai (aperchomai), which means "to go away," and "to depart." In the special case of its use with eis (as it is here), it means "departure from one place and arrival at another."

"Punishment" is from kolasis (kolasis), which primarily means "checking the growth of trees," and from that idea, "chastisement" and "correction." This is the only time this word is used in the Gospels.