1 not legally or officially acceptable:
The treaty was declared invalid because it had not been ratified. * People with invalid papers are deported to another country.
2 not based on all the facts, and therefore not correct:
an invalid argument
3 (computing) of a type that the computer cannot recognize:
An error code will be displayed if any invalid information has been entered. * invalid characters
OPPVALID
noun a person who needs other people to take care of them, because of illness that they have had for a long time:
She had been a delicate child and her parents had treated her as an invalid. * his invalid wife
verb [VN] ~ sb (out)
