Famed chalice (4,5)
I believe the answer is:
holy grail
'famed chalice' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for holy grail that I've seen before include "Legendary cup used by Jesus at Last Supper" , "In legend, the cup used by Christ at the Last Supper" , "Christ's cup at the Last Supper, sought by medieval knights" , "Chalice used by Christ at the Last Supper" , "Object of search" .)