deny; say that something is untrue
Whether you believe in human environmental damage or not, you cannot gainsay that the climate is changing.
belie, gainsay, refute
she has (Gain)ed weight but is not (say)ing it which means, she is denying the fact. A (gain)st- (say) GAINSAY~ GHANTE SEY. we say ghante sey when we want to deny sumthing. so GAINSAY=GHANTE SEY= DENY