Strongly disapprove of accepting current fall in value (10)
I believe the answer is:
depreciate
'fall in value' is the definition.
'strongly disapprove of accepting current' is the wordplay.
'strongly disapprove of' becomes 'deprecate'.
'accepting' indicates putting letters inside.
'current' becomes 'i' (symbol for electric current).
'deprecate' going around 'i' is 'DEPRECIATE'.
(Other definitions for depreciate that I've seen before include "Lose value with time" , "Gradually lose value" , "Belittle; lose value" .)