A municipality confiscating papers causes bitterness (7)
I believe the answer is:
acidity
'bitterness' is the definition.
(I've seen this before)
'a municipality confiscating papers' is the wordplay.
I cannot really see how this works, but
'a' is within the answer.
'papers' could be 'id' (identification papers) and 'id' is present in the answer.
'municipality' could be 'city' (city is a kind of municipality) and 'city' is found in the remaining letters.
No letters remain.
This explanation may well be incorrect...
'causes' acts as a link.
Can you help me to learn more?
(Other definitions for acidity that I've seen before include "Sour taste" , "bite" , "Sourness, sharpness" , "Corrosive quality" , "Bitterness" .)