General Antonyms:
* Dissent: This is the most direct and common antonym, meaning disagreement or refusal to agree.
* Refusal: A clear and direct rejection of a proposal or request.
* Disagreement: A difference of opinion or lack of agreement.
* Opposition: Active resistance or hostility towards something.
* Rejection: The act of refusing to accept something.
Contextual Antonyms:
* Negation: If "assent" is used in the sense of "affirmation," then "negation" could be an antonym.
* Denial: If "assent" refers to acknowledging something as true, then "denial" could be the antonym.
* Contradiction: If "assent" is used to agree with a statement, then "contradiction" could be the antonym.
To choose the best antonym, consider the specific context in which "assent" is used.