n.
Pronunciation: ( ˌ )in- ' va-l ə d
Function: adjective
Etymology: Latin invalidus weak, from in- + validus strong ― more at VALID
Date: 1542
: not valid: a : being without foundation or force in fact, truth, or law <an invalid assumption> <declared the will invalid > b : logically inconsequent
– in · val · id · ly \ -l ē \ adverb