Travelling groupie not very good — a baddy (5)
I believe the answer is:
rogue
'a baddy' is the definition.
(I've seen this before)
'travelling groupie not very good' is the wordplay.
'travelling' is an anagram indicator.
'not' is a deletion indicator.
'very good' becomes 'pi' (old-fashioned slang for pious).
'groupie' with 'pi' removed is 'groue'.
'groue' anagrammed gives 'ROGUE'.
(Other definitions for rogue that I've seen before include "Stray" , "Bad person" , "Old Greek" , "one behaving atypically" , "Profligate" .)