Copper, say, taking time tucking into breakfast, perhaps . . . (5)
I believe the answer is:
metal
'copper say' is the definition.
(I know that Cu is a type of metal)
'time tucking into breakfast perhaps' is the wordplay.
'time' becomes 't' (abbreviation).
'tucking into' is an insertion indicator.
'breakfast perhaps' becomes 'meal' (breakfast is a kind of meal).
't' put into 'meal' is 'METAL'.
'taking' acts as a link.
(Other definitions for metal that I've seen before include "Eg, Iron or gold" , "Lead, for example" , "lead as one" , "Copper or gold, say" , "Broken stones" .)