The Collaborative International Dictionary of English v.0.48:

Goad \Goad\, n. [AS. g[=a]d; perh. akin to AS. g[=a]r a dart,
   and E. gore. See Gore, v. t.]
   A pointed instrument used to urge on a beast; hence, any
   necessity that urges or stimulates.
   [1913 Webster]

         The daily goad urging him to the daily toil.
                                                  --Macaulay.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Goad \Goad\, v. t. [imp. & p. p. Goaded; p. pr. & vb. n.
   Goading.]
   To prick; to drive with a goad; hence, to urge forward, or to
   rouse by anything pungent, severe, irritating, or inflaming;
   to stimulate.
   [1913 Webster]

         That temptation that doth goad us on.    --Shak.

   Syn: To urge; stimulate; excite; arouse; irritate; incite;
        instigate.
        [1913 Webster]

WordNet (r) 3.0 (2006):

goad
    n 1: a pointed instrument that is used to prod into a state of
         motion [syn: prod, goad]
    2: a verbalization that encourages you to attempt something;
       "the ceaseless prodding got on his nerves" [syn: goad,
       goading, prod, prodding, urging, spur, spurring]
    v 1: give heart or courage to [syn: spur, goad]
    2: urge with or as if with a goad
    3: stab or urge on as if with a pointed stick [syn: goad,
       prick]
    4: goad or provoke,as by constant criticism; "He needled her
       with his sarcastic remarks" [syn: needle, goad]