Resolution X passed by a municipality (8)
I believe the answer is:
tenacity
'resolution' is the definition.
(I know that tenacity is a type of purpose)
'x passed by a municipality' is the wordplay.
'x' becomes 'ten' (X is the Roman numeral for ten).
'passed by' becomes 'a' (I can't justify this - if you can you should believe this answer much more).
'a municipality' becomes 'city' (city is a kind of municipality).
'ten'+'a'+'city'='TENACITY'
Can you help me to learn more?
(Other definitions for tenacity that I've seen before include "Persistence, resolution" , "Ability to stick firmly to task or position" , "Perseverance in chosen course" , "Staying power" , "Firmness of hold" .)