Mother declines sum awarded by court (7)
I believe the answer is:
damages
'sum awarded by court' is the definition.
(a court may order someone to pay damages)
'mother declines' is the wordplay.
'mother' becomes 'dam' (female parent of an animal).
'declines' becomes 'ages' (decline can mean to age).
'dam'+'ages'='DAMAGES'
(Other definitions for damages that I've seen before include "Money awarded as compensation" , "Harms" , "Moneys paid as compensation for an injury" , "Money paid in compensation for loss or injury" , "weakens" .)