Lack internal revenue for doing without (10)
I believe the answer is:
abstinence
'lack' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for abstinence that I've seen before include "The avoidance of alcohol" , "Temperance" , "keeping dry" , "Not drinking" , "Practice of refraining from indulging an appetite" .)