negate

1. V-T If one thing negates another, it causes that other thing to lose the effect or value that it had. 使无效[正式]

These weaknesses negated his otherwise progressive attitude towards the staff. 这些缺点抹杀了他本来对工作人员的开明态度。

2. V-T If someone negates something, they say that it does not exist. 否定[正式]

He warned that to negate the results of elections would only make things worse. 他警告说否定选举结果只能使事态更加恶化。