Could be worse, ringing about legal document (6)
I believe the answer is:
escrow
'legal document' is the definition.
(escrow is a kind of legal document)
'could be worse ringing about' is the wordplay.
'could be' indicates anagramming the letters.
'ringing' indicates putting letters inside.
'about' becomes 'c' (abbreviation for 'circa').
'worse' is an anagram of 'esrow'.
'esrow' enclosing 'c' is 'ESCROW'.
(Other definitions for escrow that I've seen before include "Legal deed to take effect when a condition is fulfilled" , "Legal instrument" , "document held by third party" , "Conditional deed held by third party" , "back-up security" .)