IPA: /nɒnˈvælɪdəti/
KK: /nɑnˈvælɪdəti/
The state or condition of not being valid or acceptable.
The nonvalidity of the document led to its rejection by the authorities.
Nonvalidity → It is formed from "non-" (meaning not) and "validus" (from Latin, meaning strong or effective) and the suffix "-ity" (meaning the state or condition of). The word "nonvalidity" refers to the state of being not valid or ineffective.
Think of 'not' ('non-') and 'strong' or 'effective' ('validus') to remember that 'nonvalidity' means the state of being not valid.