Very legal to go topless (5)
I believe the answer is:
awful
'very' is the definition.
(thesaurus)
'legal to go topless' is the wordplay.
'legal' becomes 'lawful' ('lawful' is associated in meaning with 'legal').
'to go topless' means to remove the first letter.
'lawful' with its initial letter removed is 'AWFUL'.
(Other definitions for awful that I've seen before include "Very poor" , "rubbish" , "The pits" , "Exceptionally bad" , "Disgusting" .)