Grunge band, unconvincing here, finally shows bite (4)
I believe the answer is:
edge
'bite' is the definition.
(thesaurus)
'grunge band unconvincing here finally' is the wordplay.
'finally' suggests the final letters.
The final letters of 'grunge band unconvincing here' are 'EDGE'.
'shows' is the link.
(Other definitions for edge that I've seen before include "Guitarist with U2" , "Final line" , "Rim or slight advantage" , "The part farthest from the middle" , "Verge" .)