The Collaborative International Dictionary of English v.0.48:

Legator \Leg`a*tor"\ (l[e^]g`[.a]*t[^o]r"), n. [L., fr. legare:
   cf. OF. legateur. See Legacy.] (Law)
   A testator; one who bequeaths a legacy. --Dryden.
   [1913 Webster]