Source : Webster's Revised Unabridged Dictionary (1913)

Tough \Tough\, a. [Compar. {Tougher}; superl. {Toughest}.] [OE.
   tough, AS. t[=o]h, akin to D. taai, LG. taa, tage, tau, OHG.
   z[=a]hi, G. z[aum]he, and also to AS. getenge near to, close
   to, oppressive, OS. bitengi.]
   1. Having the quality of flexibility without brittleness;
      yielding to force without breaking; capable of resisting
      great strain; as, the ligaments of animals are remarkably
      tough. ``Tough roots and stubs. '' --Milton.

   2. Not easily broken; able to endure hardship; firm; strong;
      as, tough sinews. --Cowper.

            A body made of brass, the crone demands, . . . Tough
            to the last, and with no toil to tire. --Dryden.

            The basis of his character was caution combined with
            tough tenacity of purpose.            --J. A.
                                                  Symonds.

   3. Not easily separated; viscous; clammy; tenacious; as,
      tough phlegm.

   4. Stiff; rigid; not flexible; stubborn; as, a tough bow.

            So tough a frame she could not bend.  --Dryden.

   5. Severe; violent; as, a tough storm. [Colloq.] `` A tough
      debate. '' --Fuller.

   {To make it tough}, to make it a matter of difficulty; to
      make it a hard matter. [Obs.] --Chaucer.