Crib clue compiled for melting pot (8)
I believe the answer is:
crucible
'melting pot' is the definition.
('crucible' can be a synonym of 'melting pot')
'crib clue compiled' is the wordplay.
'compiled' indicates anagramming the letters.
'crib'+'clue'='cribclue'
'cribclue' with letters rearranged gives 'CRUCIBLE'.
'for' acts as a link.
(Other definitions for crucible that I've seen before include "Melting-pot" , "Melting pot" , "Container for melting metal" , "Pot in which metals are melted" , "it gets very heated" .)