Hawaii Revised Statutes Division 3. Property; Family § 560:2-213

(a) The right of election of a surviving spouse or reciprocal beneficiary and the rights of the surviving spouse or reciprocal beneficiary to homestead allowance, exempt property, and family allowance, or any of them, may be waived, wholly or partially, before or after marriage, by a written contract, agreement, or waiver signed by the surviving spouse or reciprocal beneficiary.

(b) A surviving spouse's or reciprocal beneficiary's waiver is not enforceable if the surviving spouse or reciprocal beneficiary proves that:

(c) An issue of unconscionability of a waiver is for decision by the court as a matter of law.

(d) Unless it provides to the contrary, a waiver of “all rights”, or equivalent language, in the property or estate of a present or prospective spouse or reciprocal beneficiary or a complete property settlement entered into after or in anticipation of separation or divorce is a waiver of all rights of elective share, homestead allowance, exempt property, and family allowance by each spouse or reciprocal beneficiary in the property of the other and a renunciation by each of all benefits that would otherwise pass to the spouse or reciprocal beneficiary from the other by intestate succession or by virtue of any will executed before the waiver or property settlement.