Eager to move into silver (4)
I believe the answer is:
agog
'eager' is the definition.
(I've seen this in another clue)
'move into silver' is the wordplay.
'move' becomes 'go' (to go is to move).
'into' means one lot of letters goes inside another.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'go' placed into 'ag' is 'AGOG'.
'to' is the link.
(Other definitions for agog that I've seen before include "Eager - in suspense" , "Receptive - wide-mouthed" , "Interested, excited and eager to know more" , "In state of wide-eyed expectancy" , "Bug-eyed" .)