The Collaborative International Dictionary of English v.0.48:
Precative \Prec"a*tive\, Precatory \Prec"a*to*ry\, a. [L. precativus, precatorius, fr. precari to pray. See Precarious.] Suppliant; beseeching. --Bp. Hopkins. [1913 Webster] Precatory words (Law), words of recommendation, request, entreaty, wish, or expectation, employed in wills, as distinguished from express directions; -- in some cases creating a trust. --Jarman. [1913 Webster]