Chilled by diamonds, twice (4)
I believe the answer is:
iced
'chilled' is the definition.
(icing is a kind of chilling)
'by diamonds twice' is the wordplay.
'diamonds twice' can mean two replacements for 'diamonds'.
'by' means one lot of letters go next to another.
'diamonds' becomes 'ice' (slang term for diamonds).
'diamonds' becomes 'd' (abbreviation for the card suit diamonds).
'ice' put next to 'd' is 'ICED'.
(Other definitions for iced that I've seen before include "hidden under white crystals?" , "Made very cold" , "reduced number of degrees" , "Decorated with sugary mixture" , "Chilled; decorated" .)