What is the meaning of the phrase" null and void"?

having no legal force

The answer is (4) having no legal force.

The other options are incorrect.

• (1) scoring very less marks does not fit the meaning of the phrase. Null and void is a legal term, while scoring very less marks is an academic term.
• (2) disappointing does not fit the meaning of the phrase. Null and void is a legal term, while disappointing is an emotional term.
• (3) unreliable does not fit the meaning of the phrase. Null and void is a legal term, while unreliable is a descriptive term.