Mortar spreader (6)
I believe the answer is:
trowel
'mortar spreader' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for trowel that I've seen before include "Small hand tool for scooping" , "Gardening implement" , "Small gardening tool for lifting plants" , "Small spade" , "Small hand tool for garden" .)