noun
Expresses a negative stance toward a proposal, idea, or action. Often used in formal or written contexts.
彼の提案に不賛成の意を表明した。
I expressed my disapproval of his proposal.
その計画には不賛成だ。
I disagree with that plan.
賛成 means approval or agreement; 不賛成 is its direct antonym.
Formed from 不 (negative prefix) + 賛成 (approval, agreement).