The Collaborative International Dictionary of English v.0.48:

Testator \Tes*ta"tor\, n. [L.: cf. F. testateur.] (Law)
   A man who makes and leaves a will, or testament, at death.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "testator":
   Maecenas, Santa Claus, almoner, almsgiver, angel, assignor,
   awarder, backer, bestower, cheerful giver, conferrer, consignor,
   contributor, donator, donor, fairy godmother, feoffor, financer,
   funder, giver, grantor, imparter, lady bountiful, patron,
   patroness, philanthropist, presenter, settler, subscriber,
   sugar daddy, supporter, testate, testatrix, vouchsafer