RhymeZone: unthank definitions

Definitions of Unthank:

noun: Lack or absence of thanks or thankfulness; thanklessness; unthankfulness; ill-will.
verb: (transitive) To recant; unsay, as what has been said by way of acknowledgement.
verb: (transitive) To undo or retract one's thankfulness; negate, cancel, or revoke one's thanks.
noun: A surname.

(Definitions from Wiktionary)