Variable bit of punk now neglected (7)
I believe the answer is:
unknown
'variable' is the definition.
(unknown is a kind of variable)
'bit of punk now neglected' is the wordplay.
'bit of' indicates the answer is hidden within the clue.
'UNKNOWN' can be found hidden inside 'punk now neglected'.
(Other definitions for unknown that I've seen before include "no mystery" , "Not identified" , "Not recognized" , "Not recognised by anyone" , "Not familiar" .)