Like a horse used for a trick (6)
I believe the answer is:
'like' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for wooden that I've seen before include "Insensible" , "The lowest score may get this spoon" , "Ligneous" , "Monotonous like timber" , "Stiff, awkward" .)