Anonymous hunk now noticed partly (7)
I believe the answer is:
unknown
'anonymous' is the definition.
('unknown' can be similar in meaning to 'anonymous')
'hunk now noticed partly' is the wordplay.
'partly' says the answer is hidden in the clue.
'UNKNOWN' can be found hidden inside 'hunk now noticed'.
(Other definitions for unknown that I've seen before include "Undetermined" , "Unidentified, strange" , "Not recognized" , "Not identified" , "Unidentified - not explored" .)