1. [n]  light teasing repartee
2. [v]  be silly or tease one another; "After we relaxed, we just kidded around"

BANTER is a 6 letter word that starts with B.

1. \Ban"ter\, v. t. [ imp. & p. p. {Bantered}(?); p. pr. &
   vb. n. {Bantering}.] [Prob. corrupted fr. F. badiner to joke,
   or perh. fr. E. bandy to beat to and fro. See {Badinage}, and
   cf. {Barter} fr. OF. barater.]
   1. To address playful good-natured ridicule to, -- the person
      addressed, or something pertaining to him, being the
      subject of the jesting; to rally; as, he bantered me about
      my credulity.
            Hag-ridden by my own fancy all night, and then
            bantered on my haggard looks the next day. --W.
                                                  Irving.
   2. To jest about; to ridicule in speaking of, as some trait,
      habit, characteristic, and the like. [Archaic]
            If they banter your regularity, order, and love of
            study, banter in return their neglect of them.
                                                  --Chatham.
   3. To delude or trick, -- esp. by way of jest. [Obs.]
            We diverted ourselves with bantering several poor
            scholars with hopes of being at least his lordship's
            chaplain.                             --De Foe.
   4. To challenge or defy to a match. [Colloq. Southern and
      Western U.S.]
   

2. \Ban"ter\, n.
   The act of bantering; joking or jesting; humorous or
   good-humored raillery; pleasantry.
         Part banter, part affection.             --Tennyson.