As I've shown, wordsmith uses traps (4)
I believe the answer is:
thus
'as' is the definition.
(thesaurus)
'shown wordsmith uses traps' is the wordplay.
'traps' indicates the answer is hidden within the clue (the answer is 'trapped' somewhere in the clue).
'THUS' is hidden within 'shown wordsmith uses'.
'i've' is the link.
This may not be right. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for thus that I've seen before include "In this way" , "Consequently" , "Therefore, hence" , "'So, therefore (4)'" , "an original Christmas gift" .)