Making fast million over old craze (7)
I believe the answer is:
moorage
'making fast' is the definition.
(I've seen this before)
'million over old craze' is the wordplay.
'million over old' becomes 'moo' (this might be a standard abbreviation which I don't know about).
'craze' becomes 'rage' (synonyms).
'moo'+'rage'='MOORAGE'
Can you help me to learn more?
(Other definitions for moorage that I've seen before include "Fee paid for tying up a boat" , "Charge for leaving boat" , "Place for a ship to make fast" , "Making fast" , "The price for stopping" .)