Copper, say, sorting out melee by conservationists (7)
I believe the answer is:
element
'copper say' is the definition.
(copper is a kind of element)
'sorting out melee by conservationists' is the wordplay.
'sorting out' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'conservationists' becomes 'nt' (abbreviation for National Trust).
'melee' anagrammed gives 'eleme'.
'eleme'+'nt'='ELEMENT'
(Other definitions for element that I've seen before include "that's used in heating" , "Fundamental component" , "iron or copper, perhaps" , "Ingredient - small amount" , "He or I maybe" .)