Possibly a curse having a pause in verse (7)
I believe the answer is:
caesura
'pause in verse' is the definition.
(I've seen this in another clue)
'possibly a curse having a' is the wordplay.
'possibly' indicates anagramming the letters.
'having' means one lot of letters go next to another.
'a'+'curse'='acurse'
'acurse' anagrammed gives 'caesur'.
'caesur'+'a'='CAESURA'
(Other definitions for caesura that I've seen before include "Short pause in a line of verse" , "Pause or interruption (in conversation or prose)" , "Break in line" , "Pause near middle of verse line" .)