Huge spending increase receives record backing (7)
I believe the answer is:
splurge
'huge spending' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'increase receives record backing' is the wordplay.
'increase' becomes 'surge' (surge is a kind of increase).
'receives' indicates putting letters inside (inserted letters are received).
'record' becomes 'L-P' (abbreviation for long play record).
'backing' shows that the letters should be reversed in order.
'lp' reversed gives 'pl'.
'surge' enclosing 'pl' is 'SPLURGE'.
Can you help me to learn more?
(Other definitions for splurge that I've seen before include "Lash out" , "Spend wildly" , "Fork out" , "Extravagant spending spree" , "Spend lavishly" .)