Source : Webster's Revised Unabridged Dictionary (1913)

Painful \Pain"ful\, a.
   1. Full of pain; causing uneasiness or distress, either
      physical or mental; afflictive; disquieting; distressing.
      --Addison.

   2. Requiring labor or toil; difficult; executed with
      laborious effort; as a painful service; a painful march.

   3. Painstaking; careful; industrious. [Obs.] --Fuller.

            A very painful person, and a great clerk. --Jer.
                                                  Taylor.

            Nor must the painful husbandman be tired. --Dryden.

   Syn: Disquieting; troublesome; afflictive; distressing;
        grievous; laborious; toilsome; difficult; arduous. --
        {Pain"ful*ly}, adv. -- {Pain"ful*ness}, n.

Source : WordNet®

painfulness
     n : emotional distress; a fundamental feeling that people try to
         avoid; "the pain of loneliness" [syn: {pain}] [ant: {pleasure}]