Formerly quiet, legitimate and clear (8)
I believe the answer is:
explicit
'clear' is the definition.
(I've seen this before)
'formerly quiet legitimate' is the wordplay.
'formerly' becomes 'ex' (prefix meaning former or onetime).
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'legitimate' becomes 'licit' (synonyms).
'ex'+'p'+'licit'='EXPLICIT'
'and' is the link.
(Other definitions for explicit that I've seen before include "Stated without concealment" , "Clearly depicted" , "Unambiguous" , "Stated or shown directly, not ambiguous" , "Clearly shown or stated" .)