Learn Swedish: Han är fullkomligt utslagen eftersom smärtan är helt övermäktig. - He is absolutely knocked out since the pain is completely overwhelming.

This is because utslagen (knocked out) and övermäktig (insurmountable) are non-gradable adjectives. You cannot be "very" knocked out; you either are or you aren't. Therefore, you must use absolute modifiers like fullkomligt (absolutely) and helt (completely) rather than words that express a scale.

What exactly does utslagen mean in this context?

While utslagen comes from att slå ut (to knock out) and can refer to a boxer being physically unconscious, in everyday Swedish it is often used to mean being completely incapacitated, bedridden, or drained of all energy. Here, the pain has rendered him entirely unable to function.

How does the word övermäktig translate to "overwhelming"?

It breaks down literally into över (over) and mäktig (powerful). When a feeling, task, or opponent is övermäktig, it means it is too powerful for you to handle or defeat. "Overwhelming" or "insurmountable" captures this perfectly.

Since smärtan is an en-word, why does helt have a t-ending instead of being spelled hel?