Mad when “anise” is misspelled, with an extra N (6)
I believe the answer is:
insane
'mad' is the definition.
(I know that mad can be written as insane)
'is misspelled with an extra n' is the wordplay.
'misspelled with' indicates anagramming the letters (I've seen this in other clues).
'extra n' becomes 'ne' (I can't explain this - if you can you should give a lot more credence to this answer).
'is' anagrammed with 'an' makes 'insa'.
'insa'+'ne'='INSANE'
'when anise' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for insane that I've seen before include "Quite mad" , "Stupid" , "Harebrained" , "Wild < cuckoo < cracked" , "Out of one's mind" .)