Source : Webster's Revised Unabridged Dictionary (1913)

Affair \Af*fair"\ ([a^]f*f[^a]r"), n. [OE. afere, affere, OF.
   afaire, F. affaire, fr. a faire to do; L.. ad + facere to do.
   See {Fact}, and cf. {Ado}.]
   1. That which is done or is to be done; matter; concern; as,
      a difficult affair to manage; business of any kind,
      commercial, professional, or public; -- often in the
      plural. ``At the head of affairs.'' --Junius. ``A talent
      for affairs.'' --Prescott.

   2. Any proceeding or action which it is wished to refer to or
      characterize vaguely; as, an affair of honor, i. e., a
      duel; an affair of love, i. e., an intrigue.

   3. (Mil.) An action or engagement not of sufficient magnitude
      to be called a battle.

   4. Action; endeavor. [Obs.]

            And with his best affair Obeyed the pleasure of the
            Sun.                                  --Chapman.

   5. A material object (vaguely designated).

            A certain affair of fine red cloth much worn and
            faded.                                --Hawthorne.

Source : WordNet®

affair
     n 1: a vaguely specified concern; "several matters to attend to";
          "it is none of your affair"; "things are going well"
          [syn: {matter}, {thing}]
     2: a usually secretive or illicit sexual relationship [syn: {affaire},
         {intimacy}, {liaison}, {involvement}, {amour}]
     3: a vaguely specified social event; "the party was quite an
        affair"; "an occasion arranged to honor the president"; "a
        seemingly endless round of social functions" [syn: {occasion},
         {social occasion}, {function}, {social function}]