Verse in translation, initially extremely hard (6)
I believe the answer is:
severe
'hard' is the definition.
(I've seen this before)
'verse in translation initially extremely' is the wordplay.
'in translation' indicates an anagram (I've seen this in other clues).
'initially' indicates taking the first letters.
The initial letter of 'extremely' is 'e'.
'verse' is an anagram of 'sever'.
'sever'+'e'='SEVERE'
(Other definitions for severe that I've seen before include "Very bad" , "Strict, stark" , "Acute" , "Sharp" , "Stern or stringent" .)