Drop weed carelessly into ground (8)
I believe the answer is:
powdered
'ground' is the definition.
(powdering is a kind of grinding)
'drop weed carelessly' is the wordplay.
'carelessly' indicates anagramming the letters.
'drop'+'weed'='dropweed'
'dropweed' anagrammed gives 'POWDERED'.
'into' is the link.
(Other definitions for powdered that I've seen before include "wearing cosmetic" , "Reduced to dust" , "ground" .)