null and void

adjective

1. without value, effect, consequence, or significance.
2. being or amounting to nothing; nil; lacking; nonexistent.
3. Mathematics. (of a set)
   1. empty.
   2. of measure zero.
4. being or amounting to zero.

noun

5. Electronics. a point of minimum signal reception, as on a radio direction finder or other electronic meter.

verb (used with object)

6. to cancel; make null.

Idioms

7. null and void, without legal force or effect; not valid: This contract is null and void.

adjective

1. without legal force; invalid; (esp in the phrase null and void)
2. without value or consequence; useless
3. lacking distinction; characterlessa null expression
4. nonexistent; amounting to nothing
5. maths
   1. quantitatively zero
   2. relating to zero
   3. (of a set) having no members
   4. (of a sequence) having zero as a limit
6. physics involving measurement in which an instrument has a zero reading, as with a Wheatstone bridge

adj.“void of legal force,” 1560s, from Middle French nul, from Latin nullus “not any, none,” from ne- “not, no” (see un-) + illus “any,” diminutive of unus “one” (see one).

1. Of or relating to a set having no members or to zero magnitude.

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.