Brief relations ceased, not unexpectedly (9)
I believe the answer is:
anecdotes
'brief relations' is the definition.
(stories which can be told or related briefly)
'ceased not unexpectedly' is the wordplay.
'unexpectedly' is an anagram indicator.
'ceased'+'not'='ceasednot'
'ceasednot' with letters rearranged gives 'ANECDOTES'.
(Other definitions for anecdotes that I've seen before include "Noted case (anag.)" , "A short amusing story, probably true" , "yarns" , "Amusing short tales" , "Short accounts of incidents" .)