Invalid

How to spell invalid

7 letters · 3 syllables

How to pronounce invalid

Say the part in capitals loudest.

What does invalid mean?

1. adjectiveNot legally or logically sound; having no force or effect.

Invalid in a sentence

• The contract was declared invalid because it lacked a signature.

• The software rejected the password as invalid after three attempts.

Where does invalid come from?

Language of origin: Latin

This word comes from the Latin invalidus, meaning 'not strong' or 'weak', which was built from the negative prefix in- ('not') and validus ('strong, powerful'). That adjective in turn rests on the verb valere, meaning 'to be strong' or 'to be well', the same root that gives us 'value', 'valiant' and 'prevail'. English took the word in during the 1500s, first in the sense of something lacking legal or logical force, that is, 'not sound'. By the 1600s the same spelling came to name a person weakened by illness or injury, and that medical use shifted its stress to the first syllable so that two pronunciations now share one spelling. The shared validus root is a handy reminder that whether an argument or a body is 'invalid', the idea underneath is simply 'not strong'.

How the word is built

• in- (not)
• valid (strong, sound), from Latin validus 'strong'