1. [n]  a pointed instrument used to prod into motion
2. [n]  a verbalization that encourages you to attempt something; "the ceaseless prodding got on his nerves"
3. [v]  goad or provoke,as by constant criticism; "He needled her with his sarcastic remarks"
4. [v]  prod or urge as if with a log stick
5. [v]  urge with or as if with a goad
6. [v]  give heart or courage to

GOAD is a 4 letter word that starts with G.

1. \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.
   
         The daily goad urging him to the daily toil.
                                                  --Macaulay.
   
   

2. \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.
   
         That temptation that doth goad us on.    --Shak.
   
   Syn: To urge; stimulate; excite; arouse; irritate; incite;
        instigate.
   
   

(Heb. malmad, only in Judg. 3: 31), an instrument used by ploughmen for guiding their oxen. Shamgar slew six hundred Philistines with an ox-goad. "The goad is a formidable weapon. It is sometimes ten feet long, and has a sharp point. We could now see that the feat of Shamgar was not so very wonderful as some have been accustomed to think."

In 1 Sam. 13:21, a different Hebrew word is used, _dorban_, meaning something pointed. The expression (Acts 9:5, omitted in the R.V.), "It is hard for thee to kick against the pricks", i.e., against the goad, was proverbial for unavailing resistance to superior power.