from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
DISAFFIRMANCE. The act by which a person who has entered into a voidable
contract; as, for example, an infant, does disagree to such contract, and
declares he will not abide by it.
2. Disaffirmance is express or implied. The former, when the
declaration is made in terms that the party will not abide by the contract.
The latter, when he does an act which plainly manifests his determination
not to abide by it; as, where an infant made a deed for his land, and, on
coming of age, be made a deed for the same land to another. 2 Dev. & Bat.
320; 10 Pet. 58; 13 Mass. 371, 375.