The Collaborative International Dictionary of English v.0.48:
Supplicate \Sup"pli*cate\, v. t. [imp. & p. p. Supplicated; p.
pr. & vb. n. Supplicating.] [L. supplicatus, p. p. of
supplicare to supplicate; of uncertain origin, cf. supplex,
supplicis, humbly begging or entreating; perhaps fr. sub
under + a word akin to placare to reconcile, appease (cf.
Placable), or fr. sub under + plicare to fold, whence the
idea of bending the knees (cf. Ply, v. t.). Cf. Supple.]
1. To entreat for; to seek by earnest prayer; to ask for
earnestly and humbly; as, to supplicate blessings on
Christian efforts to spread the gospel.
2. To address in prayer; to entreat as a supplicant; as, to
supplicate the Deity.
Syn: To beseech; entreat; beg; petition; implore; importune;
solicit; crave. See Beseech.