invalid in‧val‧id [ɪnˈvæld] adjective
1. LAW an invalid contract, agreement, document etc is not legally or officially acceptable:

• Wellcome's patent to the drug was ruled invalid because the company didn't invent the compound.

• evidence obtained using invalid warrants

2. not based on true facts and therefore not right:

• The promotions lacked balance and made invalid comparisons between rival products.

3. COMPUTING if something that you type into a computer is invalid, the computer does not recognize or accept it:

• The date is in an invalid format.

— invalidity noun [uncountable] :

• The bonds are perforated with small holes to show their invalidity.

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invalidity UK US /ˌɪnvəˈlɪdəti/ noun [U]
the fact of not being legally or officially acceptable: »

The company was fully aware of the invalidity of its patent.

GOVERNMENT the condition of being unable to work because of health problems, and receiving money from a government or organization because of this : »

The ex-soldier receives an invalidity pension from the Army.

Financial and business terms. 2012.