Dissent

Sticker art arguing that dissent is necessary for democracy.

Dissent is an opinion, philosophy or sentiment of non-agreement or opposition to a prevailing idea or policy enforced under the authority of a government, political party or other entity or individual. A dissenting person may be referred to as a dissenter.

The term's antonyms include agreement, consensus (when all or nearly all parties agree on something) and consent (when one party agrees to a proposition made by another).