nullify
	英 ['nʌlɪfaɪ]
美['nʌlɪ'fai]
	    
    英英释意
	
	- 1. declare invalid;
 - "The contract was annulled"
 - "void a plea"
 
- 2. show to be invalid
 
- 3. make ineffective by counterbalancing the effect of;
 - "Her optimism neutralizes his gloom"
 - "This action will negate the effect of my efforts"