There's a point at which she shows wild passion (5)
I believe the answer is:
irene
'at which she shows wild passion' is the definition.
The definition suggests a singular noun which matches the answer.
'there's a point' is the wordplay.
'there's a' becomes 'ir' (I can't justify this - if you can you should give a lot more credence to this answer).
'point' becomes 'ENE' (ENE is an example).
'ir'+'ene'='IRENE'
Can you help me to learn more?
(Other definitions for irene that I've seen before include "Girl's name; Soames Forsyte's first wife" , "woman" , "US actress, -- Dunne" , "- - Handl, actress" , "In Greek mythology, the goddess of peace" .)