Copper, say, married terribly late (5)
I believe the answer is:
metal
'copper say' is the definition.
(I know that Cu is a type of metal)
'married terribly late' is the wordplay.
'married' becomes 'm'.
'terribly' indicates anagramming the letters.
'late' with letters rearranged gives 'etal'.
'm'+'etal'='METAL'
(Other definitions for metal that I've seen before include "Tungsten, for example" , "Material detectable in the ground" , "Iron, gold or silver, for example" , "Copper possibly" , "Broken stones" .)