In the clue for “newt” made a mistake (4,5)
I believe the answer is:
went wrong
'in the clue for newt made a mistake' is the definition.
I can't tell whether this defines the answer.
'in the clue for newt made' is the wordplay.
'in the' means one lot of letters goes inside another.
'clue for' becomes 'wrong' (I am not sure about this - if you are sure you should believe this answer much more).
'made' is an anagram indicator.
'newt' is an anagram of 'entw'.
'wrong' enclosing 'entw' is 'WENT WRONG'.
Can you help me to learn more?
(Another definition for went wrong that I've seen is " Made an error".)