negate
v.v. to make something useless or to cancel its effect. In computing, it means to change the value of a variable to the opposite of what it was.
v. to make something ineffective or to cancel the effect of something else. In a logical or programming context, it refers to the operation that inverts the truth value of a proposition or the state of a variable.
The new law will negate the previous agreement.
In programming, you use the 'not' operator to negate a boolean value, turning true into false and vice versa.
The proposed tax reform may negate the benefits of the previous stimulus package, effectively nullifying the intended economic recovery by increasing the cost of living for consumers.
From Latin negātus, perfect passive participle of negō (“to deny, refuse, decline”), see -ate (verb-forming suffix).