The Collaborative International Dictionary of English v.0.48:

Suppliant \Sup"pli*ant\, n.
   One who supplicates; a humble petitioner; one who entreats
   submissively.
   [1913 Webster]

         Hear thy suppliant's prayer.             --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Suppliant \Sup"pli*ant\, a. [F., p. pr. of supplier to entreat,
   L. supplicare. See Supplicate, and cf. Supplicant.]
   1. Asking earnestly and submissively; entreating; beseeching;
      supplicating.
      [1913 Webster]

            The rich grow suppliant, and the poor grow proud.
                                                  --Dryden.
      [1913 Webster]

   2. Manifesting entreaty; expressive of supplication.
      [1913 Webster]

            To bow and sue for grace
            With suppliant knee.                  --Milton.
      [1913 Webster]

   Syn: Entreating; beseeching; suing; begging; supplicating;
        imploring.
        [1913 Webster] -- Sup"pli*ant*ly, adv. --
        Sup"pli*ant*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

suppliant
    adj 1: humbly entreating; "a suppliant sinner seeking
           forgiveness" [syn: suppliant, supplicant,
           supplicatory]
    n 1: one praying humbly for something; "a suppliant for her
         favors" [syn: petitioner, suppliant, supplicant,
         requester]