See dissent in Webster's New World Roget's A-Z Thesaurus II
verb
To be of different opinion:
differ, disaccord, disagree, discord, vary. Idiom: join (or take) issue. See agree
noun
A state of disagreement and disharmony:
clash, conflict, confrontation, contention, difference, difficulty, disaccord, discord, discordance, dissension, dissentience, dissidence, dissonance, faction, friction, inharmony, schism, strife, variance, war, warfare. See conflict
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