Penelope is spinning with mania in hallucination (6)
I believe the answer is:
mirage
'hallucination' is the definition.
(I've seen this before)
'penelope is spinning with mania' is the wordplay.
'penelope' becomes 'im' (I can't justify this - if you can you should believe this answer much more).
'is spinning' shows that the letters should be reversed in order.
'with' means one lot of letters go next to another.
'mania' becomes 'rage' (I've seen this in another clue).
'im' written backwards gives 'mi'.
'mi'+'rage'='MIRAGE'
'in' is the link.
Can you help me to learn more?
(Other definitions for mirage that I've seen before include "French flier" , "French fighter aircraft" , "See it to believe it?" , "Illusions in the desert" , "Hallucination caused by hot air" .)