Keepers at zoo looking after cod (6)
I believe the answer is:
ersatz
'cod' is the definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?
'keepers at zoo looking' is the wordplay.
'ERSATZ' is hidden in amongst the letters.
But, I'm uncertain how this is indicated.
'after' acts as a link.
Can you help me to learn more?
(Other definitions for ersatz that I've seen before include "Imitation, not the real thing" , "Made in imitation - in Germany" , "'Artificial, not genuine (6)'" , "Imitation or substitute, from German" , "unnatural" .)