What's the noun for dissenter? Here's the word you're looking for.
dissent
Disagreement with the ideas, doctrines, decrees, etc. of a political party, government or religion.
An act of disagreeing with, or deviating from, the views and opinions of those holding authority.
(Anglo-American common law) A separate opinion filed in a case by judges who disagree with the outcome of the majority of the court in that case
(sports) A violation that arises when disagreement with an official call is expressed in an inappropriate manner such as foul language, rude gestures, of failure to comply.
“This was Kant's judicious way of amending Rousseau's notorious maxim, that, in a state founded on the social contract, the dissenter must be forced to be free.”
“The dissenter was proud of their decision to join the non-established Church.”
“While Pinter the playwright may extol existential ambiguity and incertitude, Pinter the activist and dissenter has no such anxiety.”
dissental
(US, law, colloquial) A dissent from an order denying rehearing en banc.
“The poetry of dissidence and resistance on the other hand has to create its own space, which is public as well as private, real as well as virtual.”
“Despite the overall consensus within the party, Sarah's dissidence on the issue of tax policy sparked intense debates and challenged the traditional views held by fellow members.”
“Nobody seemed to know who was putting this out, but its dissidence was a welcome antidote to the blandness of mainstream public radio.”
“However, it is not clear if this was the reality, and there were many dissentients from this thesis.”
“Views of these kinds, with their roots mainly in clinical observation and practice, held sway with many variations and some dissentients well into the twentieth century.”
“Taking his seat the next year, the split emerged within weeks, when he became one of two dissentients to the historic 1973 Roe v Wade judgment, which legalised abortion throughout America.”