
Rebut
Denying Assertions
 Use 'rebut' when you need to firmly deny what someone says, especially when you have proof. 
Politicians often rebut accusations in debates.
 Strong Defense
 'Rebut' suggests a strong response or comeback to challenge a statement or belief. 
The scientist rebutted the theory with new evidence.
 Not Merely Denial
 'Rebut' is stronger than just saying 'no' as it usually involves explaining why the other point is wrong. 
He didn't just say no; he rebutted every point with facts.