Not wholly backing Odysseus's imminent release (5)
I believe the answer is:
issue
'release' is the definition.
(I know that release is a more specific form of issue)
'not wholly backing odysseus's imminent' is the wordplay.
'backing' shows that the letters should be reversed in order.
'not wholly' indicates the answer is hidden within the clue (I've seen this in other clues).
'eussi' is hidden in the letters of 'odysseuss imminent'.
'eussi' back-to-front is 'ISSUE'.
(Other definitions for issue that I've seen before include "Important topic for offspring" , "Regular publication" , "Result, outcome; topic" , "Continent" , "Contentious point" .)