Available Definitions:
1) v. t. - To assert the contrary of; to oppose in words; to take issue with; to gainsay; to deny the truth of, as of a statement or a speaker; to impugn.
2) v. t. - To be contrary to; to oppose; to resist.
3) v. i. - To oppose in words; to gainsay; to deny, or assert the contrary of, something.