What is Rebut?

Legal Definition
To contradict; to do away as, every homicide is presumed to be murder, unless the contrary appears from evidence which proves the death; and this presumption it lies on the defendant to rebut by showing that it was justifiable or excusable. Allis. Prin. 48.
-- Bouviers Law Dictionary
Legal Definition
In pleading and evidence. To rebut is to defeat or take away the effect of something. Thus, when a plaintiff in an action produces evidence which raises a presumption of the defendant's liability, and the defendant adduces evidence which shows that the presumption is ill-founded, he is said to "rebut it." Sweet. In the old law of real property, to rebut was to repel or bar a claim. Thus, when a person was sued for land which had been warranted to him by the plaintiff or hla ancestor, and he pleaded the warranty as a defense to the action, this was called a "rebutter." Co. Litt 365a; Termes de 1a Ley. See Rebut an equity.
-- Black's Law Dictionary
Legal Definition
To deny; to contradict; to avoid.
-- Ballentine's Law Dictionary