Cliché without legal force; having no legal effect. The court declared the law to be null and void.The millionaire's will was null and void because it was unsigned.
to replace something important that you have lost, or to provide something important that you need The country needs a strong leader to help fill the void left by the death of the president.Religion helped me fill a void in my life.
Canceled, invalid, as in The lease is now null and void. This phrase is actually redundant, since null means "void," that is, "ineffective." It was first recorded in 1669.