Heard expression, crude perhaps, in confusion (7)
I believe the answer is:
turmoil
'confusion' is the definition.
(I've seen this before)
'heard expression crude perhaps' is the wordplay.
'heard expression' becomes 'turm' (I am not sure about this - if you are sure you should believe this answer much more).
'crude perhaps' becomes 'oil' (crude is a kind of oil).
'turm'+'oil'='TURMOIL'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for turmoil that I've seen before include "State of great disturbance or confusion" , "Sturm und Drang" , "Uproar" , "upset" , "Tumult, upheaval" .)