"At Seventeen" singer Janis (3)
I believe the answer is:
ian
'at seventeen singer janis' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ian that I've seen before include "Albert Beale's first name in EastEnders" , "The familiar Mr Paisley" , "Boy's name (Scottish?)" , "Botham or Chappell?" , "Scotsman?" .)