Stout old Spaniard backing zero carbon - about time (6)
I believe the answer is:
cortez
'stout old spaniard backing' is the definition.
The definition suggests a singular noun which matches the answer.
'zero carbon about time' is the wordplay.
'carbon' becomes 'C' (C is the chemical symbol for carbon).
'about' indicates an anagram.
'time' becomes 't' (abbreviation).
'zero'+'c'='zeroc'
'zeroc' mixed up with 't' makes 'CORTEZ'.
Can you help me to learn more?
(Other definitions for cortez that I've seen before include "Spaniard who defeated the Aztecs and conquered Mexico" , "Spanish conquistador Keats had 'Silent, upon a peak in Darien'" , "Spanish conquistador (Z, not S)" .)