One prompting motion reconstituting a vile tax (8)
I believe the answer is:
laxative
'one' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
'prompting motion reconstituting a vile tax' is the wordplay.
'a vile tax' can be anagrammed to 'LAXATIVE'.
Though, I'm unsure how this is indicated.
Can you help me to learn more?
(Other definitions for laxative that I've seen before include "Aperient medicine" , "Medicine for constipation" , "Purgative, loosener" .)