Counterargument

In reasoning and argument mapping, a counter argument, also known as a rebuttal, is an objection to an objection. A counterargument can be used to rebutt an objection to a premise, a main contention or a lemma.A counter argument might seek to cast doubt on the truth of one or more of the first argument's premises, or to show that the first argument's contention does not follow from its premises in a valid manner, or the counter argument might pay little attention to the premises and inference structure of the first argument and simply attempt to demonstrate the truth of a conclusion incompatible with that of the first argument.
See more at Wikipedia.org...

Noun
1. an argument offered in opposition to another argument
(hypernym) argument, statement