Powerful number about teenager, gutted (6)
I believe the answer is:
strong
'powerful' is the definition.
(similar in meaning)
'number about teenager gutted' is the wordplay.
'number' becomes 'song' (I've seen this in another clue).
'about' indicates putting letters inside.
'gutted' suggests removing the centre (to gut something is to remove its insides).
'teenager' with its middle taken out is 'tr'.
'song' placed around 'tr' is 'STRONG'.
(Other definitions for strong that I've seen before include "Able to withstand attack" , "Resilient" , "Physically powerful - feel 1 Across" , "Not faint or feeble" , "Potent" .)