Timber-dressing tool (4)
I believe the answer is:
adze
'timber-dressing tool' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for adze that I've seen before include "Wood-cutting tool" , "Carpenter's tool sound mathematically capable" , "Carpenter's tool sounds mathematical" , "Tool for shaping timber" , "Edge tool used to cut and shape wood" .)