1. sound; just; well-founded: a valid reason.
  2. producing the desired result; effective: a valid antidote for gloom.
  3. having force, weight, or cogency; authoritative.
  4. legally sound, effective, or binding; having legal force: a valid contract.
  5. Logic. (of an argument) so constructed that if the premises are jointly asserted, the conclusion cannot be denied without contradiction.
  6. Archaic. robust; well; healthy.

Origin of valid

1565–75; < Latin validus strong, equivalent to val(ēre) to be strong + -idus -id4
Related formsval·id·ly, adverbval·id·ness, nounnon·val·id, adjectivenon·val·id·ly, adverbnon·val·id·ness, nounpre·val·id, adjectivepre·val·id·ly, adverbqua·si-val·id, adjectivequa·si-val·id·ly, adverb
Can be confusedvalet valid

Synonyms for valid Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for non-valid

Historical Examples of non-valid

British Dictionary definitions for non-valid


  1. having some foundation; based on truth
  2. legally acceptablea valid licence
    1. having legal force; effective
    2. having legal authority; binding
  3. having some force or cogencya valid point in a debate
  4. logic (of an inference or argument) having premises and conclusion so related that whenever the former are true the latter must also be true, esp (formally valid) when the inference is justified by the form of the premises and conclusion alone. Thus Tom is a bachelor; therefore Tom is unmarried is valid but not formally so, while today is hot and dry; therefore today is hot is formally validCompare invalid 2 (def. 2)
  5. archaic healthy or strong
Derived Formsvalidly, adverbvalidity (vəˈlɪdɪtɪ) or validness, noun

Word Origin for valid

C16: from Latin validus robust, from valēre to be strong
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for non-valid



1570s, "having force in law, legally binding," from Middle French valide, from Latin validus "strong, effective," from valere "be strong" (see valiant). The meaning "supported by facts or authority" is first recorded 1640s.

Online Etymology Dictionary, © 2010 Douglas Harper