The premises on which he based his conclusions were invalid.
Like telling someone.. "Is an invalid sentence." would be incorrect. "That is an invalid sentence." would be correct.
the little boy in the wheel chair is an invalid person. Invalid means sick, disabled, or diseased person
My neighbor is an invalid.
I forgot to renew my licence and now it is invalid.
Example sentence - The ticket was invalid because the expiration date had passed.
The credit card was invalid; it was not approved at checkout.
The old man was an invalid; he could no longer take care of himself.
She signed the contract under duress, fearing the consequences if she did not comply with the demands.
The adjective 'invalid' has two different meanings:1) Not legally factual; without foundation in fact or law; falsely based or reasoned.2) Incapacitated by illness or injury.Example sentences:1) He was driving with an invalid license which had expired months ago.2) That space is marked as 'invalid parking', let's check the next row.
The certificates was invalidated by the superiors
The lottery ticket proved to be invalid when he attempted to collect the prize.
.invalid was created in 1999.