Cinchona alkaloid for one of five in Evans Head? (7)
I believe the answer is:
quinine
'cinchona alkaloid' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'one of five in evans head?' is the wordplay.
'one of five' becomes 'quin' (short for quintuplet, one of five children).
'head?' says to take the initial letters (I've seen 'head of' mean this).
The first letter of 'evans' is 'e'.
'quin'+'in'+'e'='QUININE'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for quinine that I've seen before include "Bitter compound used as a tonic" , "Substance used in treating malaria" , "Fever-reducing drug" , "Alkaloid from tree" , "Tonic flavouring" .)