Tears the material - and tears badly (9)
I believe the answer is:
lacerates
'tears' is the definition.
(lacerating is a kind of tearing)
'the material and tears badly' is the wordplay.
'the material' becomes 'lace' (lace is a kind of material**).
'and' means one lot of letters go next to another.
'badly' indicates anagramming the letters.
'tears' anagrammed gives 'rates'.
'lace'+'rates'='LACERATES'
(Other definitions for lacerates that I've seen before include "Cuts (flesh) roughly" , "Tear" .)