To give a false representation to; misrepresent: "He spoke roughly in order to belie his air of gentility” ( James Joyce).
To show to be false; contradict: Their laughter belied their outward grief.
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.