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in·va·lid 1 (ĭnvə-lĭd)
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n.
One who is incapacitated by a chronic illness or disability.
adj.
1. Incapacitated by illness or injury.
2. Of, relating to, or intended for invalids.
tr.v. in·va·lid·ed, in·va·lid·ing, in·va·lids
1. To incapacitate physically.
2. Chiefly British To release or exempt from duty because of ill health: "I was not quite sick enough to be invalided out, even though I was of no more use" (Mary Lee Settle).

[From INVALID2 (influenced by French invalide, sickly, infirm).]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 
in·val·id 2 (ĭn-vălĭd)
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adj.
1. Not legally or factually valid; null: an invalid license.
2. Falsely based or reasoned; faulty: an invalid argument.

[Latin invalidus, weak : in-, not; see IN-1 + validus, strong (from valēre, to be strong; see wal- in the Appendix of Indo-European roots).]

inva·lidi·ty (-və-lĭdĭ-tē) n.
in·valid·ly adv.

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2017 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
 

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