Caught servant hiding key — one who sold the family silver? (6)
I believe the answer is:
cutler
'one who sold the family silver?' is the definition.
(a cutler is a maker of cutlery)
'caught servant hiding key' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'servant' becomes 'butler' (butler is a kind of servant).
'hiding' suggests deleting specific letters.
'key' becomes 'b' (eg B major, musical key).
'butler' with 'b' taken out is 'utler'.
'c'+'utler'='CUTLER'
(Other definitions for cutler that I've seen before include "He makes and sells knives, forks, spoons etc" , "Knife-maker" , "Maker of knives/forks" , "Maker or dealer in knives, forks etc" , "Knife etc. maker" .)