Publication one possibly sues (5)
I believe the answer is:
issue
'publication' is the definition.
(I know that publication can be written as issue)
'one possibly sues' is the wordplay.
'one' becomes 'i' (Roman numeral).
'possibly' indicates an anagram.
'sues' anagrammed gives 'ssue'.
'i'+'ssue'='ISSUE'
(Other definitions for issue that I've seen before include "Subject, result, or publication" , "Point in dispute" , "Pour forth" , "Give or send out" , "Point under discussion" .)