Fuzz on bottom of the brush (5)
I believe the answer is:
copse
'brush' is the definition.
(I know that brush can be written as copse)
'fuzz on bottom of the' is the wordplay.
'fuzz' becomes 'cops' (I've seen this in another clue).
'on bottom of' says to take the final letters.
The final letter of 'the' is 'e'.
'cops'+'e'='COPSE'
(Other definitions for copse that I've seen before include "Dense growth of shrubs or trees" , "Dense thicket of trees" , "Scope for a small wood" , "Clump of small trees for regular cropping" , "Cultivated woodland area" .)