Hand on tradition, ultimately giving pledge (4)
I believe the answer is:
pawn
'pledge' is the definition.
(I've seen this before)
'hand on tradition ultimately' is the wordplay.
'hand' becomes 'paw' ('paw' can be a synonym of 'hand'**).
'on' is a charade indicator (letters next to each other).
'ultimately' says to take the final letters.
The last letter of 'tradition' is 'n'.
'paw'+'n'='PAWN'
'giving' acts as a link.
(Other definitions for pawn that I've seen before include "Lodge (item) for money" , "Minor chessman" , "one used by another" , "Deposit as pledge" , "Lend uncle" .)