The Collaborative International Dictionary of English v.0.48:

Godfather \God"fa`ther\, v. t.
   To act as godfather to; to take under one's fostering care.
   [R.] --Burke.
   [1913 Webster] god"fear`ing,

The Collaborative International Dictionary of English v.0.48:

Godfather \God"fa`ther\, n. [AS. godf[ae]der. Cf. Gossip.]
   A man who becomes sponsor for a child at baptism, and makes
   himself a surety for its Christian training and instruction.
   Correlative of godmother.
   [1913 Webster]

         There shall be for every Male-child to be baptized,
         when they can be had, two Godfathers and one Godmother;
         and for every Female, one Godfather and two Godmothers;
         and Parents shall be admitted as Sponsors, if it is
         desired.                                 --Book of
                                                  Common Prayer
                                                  (Prot. Episc.
                                                  Ch., U. S. ).
   [1913 Webster]

WordNet (r) 3.0 (2006):

godfather
    n 1: any man who serves as a sponsor for a child at baptism
    2: someone having a relation analogous to that of a male sponsor
       to his godchild