Claim renouncer

• One who surrenders
• One who gives up or relinquishes or renounces something

Wiktionary Word definitions in Wiktionary
n. (context rare English) One who abnegates, denies, or rejects. (From Mid 17 th century.) (R:SOED5: page=6)

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Abnegator \Ab"ne*ga`tor\, n. [L.] One who abnegates, denies, or rejects anything. [R.] [1913 Webster] ||

WordNet Word definitions in WordNet
n. one who gives up or relinquishes or renounces something