One hundred craft a wagon (4)
I believe the answer is:
cart
'a wagon' is the definition.
(I know that cart is a type of wagon)
'one hundred craft' is the wordplay.
'one hundred' becomes 'C' (Roman numeral).
'craft' becomes 'art' (both can mean cunning or trickery).
'c'+'art'='CART'
(Other definitions for cart that I've seen before include "Two-wheeled open wagon" , "Hump" , "Heavy open wagon" , "Open wagon (to come after, not before, the horse)" , "Old two-wheeled goods vehicle" .)