My copy of Webster's Third, in one of its definitions, yields the following possibility for rebuttal: the act of exposing the falsity of, or opposition by countervailing proof to, some contention or argument.
"The Burletta of the Quest Nears,"
Word Ways: Vol. 26
, Article 17.
Available at: http://digitalcommons.butler.edu/wordways/vol26/iss2/17