Source : Webster's Revised Unabridged Dictionary (1913)

Big \Big\, a. [Compar. {Bigger}; superl. {Biggest}.] [Perh. from
   Celtic; cf. W. beichiog, beichiawg, pregnant, with child, fr.
   baich burden, Arm. beac'h; or cf. OE. bygly, Icel. biggiligr,
   (properly) habitable; (then) magnigicent, excellent, fr. OE.
   biggen, Icel. byggja, to dwell, build, akin to E. be.]
   1. Having largeness of size; of much bulk or magnitude; of
      great size; large. ``He's too big to go in there.''
      --Shak.

   2. Great with young; pregnant; swelling; ready to give birth
      or produce; -- often figuratively.

            [Day] big with the fate of Cato and of Rome.
                                                  --Addison.

   3. Having greatness, fullness, importance, inflation,
      distention, etc., whether in a good or a bad sense; as, a
      big heart; a big voice; big looks; to look big. As applied
      to looks, it indicates haughtiness or pride.

            God hath not in heaven a bigger argument. --Jer.
                                                  Taylor.

   Note: Big is often used in self-explaining compounds; as,
         big-boned; big-sounding; big-named; big-voiced.

   {To talk big}, to talk loudly, arrogantly, or pretentiously.

            I talked big to them at first.        --De Foe.

   Syn: Bulky; large; great; massive; gross.