Prisoner left with silver (3)
I believe the answer is:
lag
'prisoner' is the definition.
(slang term)
'left with silver' is the wordplay.
'left' becomes 'l' (common abbreviation).
'with' says to put letters next to each other.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'l'+'ag'='LAG'
(Other definitions for lag that I've seen before include "Fall behind or cover to prevent heat loss" , "Fall behind; insulate" , "habitual criminal?" , "An old one is a convict" , "Dawdle" .)