Possibly soft turn of phrase (7)
I believe the answer is:
perhaps
'possibly' is the definition.
(synonyms)
'soft turn of phrase' is the wordplay.
'soft' becomes 'p' (musical abbreviation for 'piano').
'turn of' is an anagram indicator (I've seen 'turned' mean this).
'phrase' is an anagram of 'erhaps'.
'p'+'erhaps'='PERHAPS'
(Other definitions for perhaps that I've seen before include "Possibly, maybe" , "Not necessarily" , "Could be, maybe" , "Possibly but not certainly" , "say" .)