Involving, of the nature of, or being a contradiction. See Synonyms at opposite.
Given to contradicting.
Logic Either of two propositions related in such a way that it is impossible for both to be true or both to be false.
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.