a difficult or hard [noun]; “is difficult” when 는 is attached to the preceding word
→ 는
phraseRare#22,830
a difficult or hard [noun]; “is difficult” when 는 is attached to the preceding word힘든 is the attributive form of 힘들다, meaning “difficult,” “hard,” or “tough,” and usually comes before a noun. 는 is a topic or contrast particle attached to the preceding word, so 는 힘든 is not a fixed phrase by itself. The exact meaning depends on the surrounding sentence.