verb
gainsay
gayn-SAY/ˌɡeɪnˈseɪ/
To deny or contradict a statement or claim.
The participant gainsays the claim, raising a palm with a skeptical expression.

Etymology
Gainsay literally means “say against”: to oppose a statement by contradicting or denying it. Its first piece preserves an old prefix expressing opposition.
In context
if you trust me I'll give you words and wisdom that none of your adversaries can gainsay nor resist
More examples
- She does not gainsay his claim to the property.
- He gainsaid my account of what happened that evening.
- Without reliable evidence, gainsaying their explanation is difficult.
Forms
gainsay · gainsays · gainsaid · gainsaying
Similar words
- deny
- Directly rejects a claim as false; more common in everyday speech.
- contradict
- Asserts something incompatible with another statement, explicitly or implicitly.
- dispute
- Challenges a claim's truth or validity, often through argument.