Nile-dweller's pupils in formation? (9)
I believe the answer is:
crocodile
'formation?' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for crocodile that I've seen before include "Large river reptile" , "Old Cicero, oddly, was a voracious reptile" , "Vicious beast" , "Predatory reptile" , "Line of children walking in twos" .)