What is Waiver?

Legal Definition
A waiver is the voluntary relinquishment or surrender of some known right or privilege.

Regulatory agencies or governments may issue waivers to exempt companies from certain regulations. For example, a United States law restricted the size of banks, but when banks exceeded these sizes, they obtained waivers. In another example, the United States federal government may issue waivers to individual states so that they may provide Medicaid in different ways than the law typically requires.

While a waiver is often in writing, sometimes a person's words can also be used as a counteract to a waiver. An example of a written waiver is a disclaimer, which becomes a waiver when accepted. When the right to hold a person liable through a lawsuit is waived, the waiver may be called an exculpatory clause, liability waiver, legal release, or hold harmless clause.

In some cases, parties may sign a "non-waiver" contract which specifies that no rights are waived, particularly if a person's actions may suggest that rights are being waived. This is particularly common in insurance, as it is less detailed than a reservation of rights letter; the disadvantage is that it requires the signature of the insured.

Sometimes the elements of "voluntary" and "known" are established by a legal fiction. In this case, one is presumed to know one's rights and that those rights are voluntarily relinquished if not asserted at the time.

In civil procedure, certain arguments must be raised in the first objection that a party submits to the court, or else they will be deemed waived.
-- Wikipedia
Legal Definition
The relinquishment or refusal to accept of a right.

2. In practice it is required of every one to take advantage of his rights at a proper time and, neglecting to do so, will be considered as a waiver. If, for example, a defendant who has been misnamed in the writ and declaration, pleads over, he cannot afterwards take advantage of the error by pleading in abatement, for his plea amounts to a waiver.

3. In seeking for a remedy the party injured may, in some instances, waive a part of his right, and sue for another; for example, when the defendant has committed a trespass on the property of the plaintiff, by taking it away, and afterwards he sells it, the injured party may waive the trespass, and bring an action of assumpsit for the recovery of the money thus received by the defendant. 1 Chit. Pl. 90.

4. In contracts, if, after knowledge of a supposed fraud, surprise or mistake, a party performs the agreement in part, he will be considered as having waived the objection. 1 Bro. Parl. Cas. 289.

5. It is a rule of the civil law, consonant with reason, that any one may renounce or waive that which has been established in his favor: Regula est juris antique omnes licentiam habere his quae pro se introducta sunt, renunciare. Code 2, 3, 29. As to what will amount to a waiver of a forfeiture, see 1 Conn. R. 79; 7 Conn. R. 45; 1 Jo Cas. 125; 8 Pick. 292; 2 N. H, Rep. 120 163; 14 Wend. 419; 1 Ham. R. 21. Vide Verdict.
-- Bouviers Law Dictionary
Legal Definition
The renunciation, repudiation, abandonment or surrender of some claim, right, privilege or of the opportunity to take advantage of some defect, irregniar-ity or wrong. The passing by of an occasion to enforce a legal right, whereby the right to ehforce the same is lost; a common instance of this is where a landlord waives a forfeiture of a lease by receiving rent, or distraining" for rent, which has accrued due after the breach of covenant causing the forfeiture became known to him. Wharton. This word is commonly used to denote the declining to take advantage of an irregularity in legal proceedings, or of a forfeiture incurred through breach of covenants in a lease. A glft of goods may be waived by a disagreement to accopt; so a plaintiff may commonly sue in contract waiving the tort. Brown. See Bennecke v. Insurance Co., 105 U. S. 355, 26 L. Ed. 990; Christenson v. Carleton, 69 Vt 91, 37 Atl. 226; Shaw v. Spencer, 100 Mass. 395, 97 Am. Dec. 107, 1 Am. Rep. 115; Star Brewery Co. v. Primas, 163 III. 652, 45 N. E. 145; Reid v. Field, 83 Va. 26, 1 S. El 395; Caulfield v. Finnegan, 114 Ain. 39, 21 South. 484; Lyman v. Littleton, 50 N. H. 54; Smiley v. Barker, 83 Fed. 684, 28 C. C. A. 9; Boos v. Ewing, 17 Ohio 523, 49 Am. Dee, 478.
See also
-- Black's Law Dictionary
Legal Definition
Intentionally or voluntarily giving up one's recognized right.
Legal Definition
An intentional relinquishment of a known right. See 66 Conn. 227, 50 Am. St. Rep. 80, 33 Atl. 902.
-- Ballentine's Law Dictionary