-내

From Middle Korean -내〯 (-nǎy). See 내 (nae, “through, throughout”), the adverb form.

-내 • (-nae)

1. through, throughout

   ‎겨울 (gyeoul, “winter”) + ‎-내 (-nae) → ‎겨우내 (gyeounae, “throughout the winter”)

2. to, until

   ‎끝 (kkeut, “end”) + ‎-내 (-nae) → ‎끝내 (kkeunnae, “until the end”)