Copper, say, encountered a novice (5)
I believe the answer is:
metal
'copper say' is the definition.
(I know that copper is a type of metal)
'encountered a novice' is the wordplay.
'encountered' becomes 'met' ('meet' can be a synonym of 'encounter').
'novice' becomes 'L' (as in a learner driver with L-plates on their car).
'met'+'a'+'l'='METAL'
(Other definitions for metal that I've seen before include "Tungsten, for example" , "Lead or iron, perhaps" , "Copper or gold, say" , "Conducting solid" , "lead as one" .)