Source : Webster's Revised Unabridged Dictionary (1913)

Uncomfortable \Un*com"fort*a*ble\, a.
   1. Feeling discomfort; uneasy; as, to be uncomfortable on
      account of one's position.

   2. Causing discomfort; disagreeable; unpleasant; as, an
      uncomfortable seat or situation.

            The most dead, uncomfortable time of the year.
                                                  --Addison.
      -- {Un*com"fort*a*ble*ness}, n. -- {Un*com"fort*a*bly},
      adv.

Source : WordNet®

uncomfortable
     adj 1: conducive to or feeling mental discomfort; "this kind of
            life can prove disruptive and uncomfortable"; "the
            uncomfortable truth"; "grew uncomfortable beneath his
            appraising eye"; "an uncomfortable way of surprising
            me just when I felt surest"; "the teacher's presence
            at the conference made the child very uncomfortable"
            [ant: {comfortable}]
     2: providing or experiencing physical discomfort; "an
        uncomfortable chair"; "an uncomfortable day in the hot
        sun" [ant: {comfortable}]