Source : Webster's Revised Unabridged Dictionary (1913)

Ease \Ease\, n. [OE. ese, eise, F. aise; akin to Pr. ais, aise,
   OIt. asio, It. agio; of uncertain origin; cf. L. ansa handle,
   occasion, opportunity. Cf. {Agio}, {Disease}.]
   1. Satisfaction; pleasure; hence, accommodation;
      entertainment. [Obs.]

            They him besought Of harbor and or ease as for hire
            penny.                                --Chaucer.

   2. Freedom from anything that pains or troubles; as:
      (a) Relief from labor or effort; rest; quiet; relaxation;
          as, ease of body.

                Usefulness comes by labor, wit by ease.
                                                  --Herbert.

                Give yourself ease from the fatigue of watching.
                                                  --Swift.
      (b) Freedom from care, solicitude, or anything that annoys
          or disquiets; tranquillity; peace; comfort; security;
          as, ease of mind.

                Among these nations shalt thou find no ease.
                                                  --Deut.
                                                  xxviii. 65.

                Take thine ease, eat, drink, and be merry.
                                                  --Luke xii.
                                                  19.
      (c) Freedom from constraint, formality, difficulty,
          embarrassment, etc.; facility; liberty; naturalness;
          -- said of manner, style, etc.; as, ease of style, of
          behavior, of address.

                True ease in writing comes from art, not chance.
                                                  --Pope.

                Whate'er he did was done with so much ease, In
                him alone 't was natural to please. --Dryden.

   {At ease}, free from pain, trouble, or anxiety. ``His soul
      shall dwell at ease.'' --Ps. xxv. 12.

   {Chapel of ease}. See under {Chapel}.

   {Ill at ease}, not at ease, disquieted; suffering; anxious.
      

   {To stand at ease} (Mil.), to stand in a comfortable attitude
      in one's place in the ranks.

   {With ease}, easily; without much effort.

   Syn: Rest; quiet; repose; comfortableness; tranquility;
        facility; easiness; readiness.

Ill \Ill\, a. [The regular comparative and superlative are
   wanting, their places being supplied by worseand worst, from
   another root.] [OE. ill, ille, Icel. illr; akin to Sw. illa,
   adv., Dan. ilde, adv.]
   1. Contrary to good, in a physical sense; contrary or opposed
      to advantage, happiness, etc.; bad; evil; unfortunate;
      disagreeable; unfavorable.

            Neither is it ill air only that maketh an ill seat,
            but ill ways, ill markets, and ill neighbors.
                                                  --Bacon.

            There 's some ill planet reigns.      --Shak.

   2. Contrary to good, in a moral sense; evil; wicked; wrong;
      iniquitious; naughtly; bad; improper.

            Of his own body he was ill, and gave The clergy ill
            example.                              --Shak.

   3. Sick; indisposed; unwell; diseased; disordered; as, ill of
      a fever.

            I am in health, I breathe, and see thee ill. --Shak.

   4. Not according with rule, fitness, or propriety; incorrect;
      rude; unpolished; inelegant.

            That 's an ill phrase.                --Shak.

   {Ill at ease}, uneasy; uncomfortable; anxious. ``I am very
      ill at ease.'' --Shak.

   {Ill blood}, enmity; resentment.

   {Ill breeding}, want of good breeding; rudeness.

   {Ill fame}, ill or bad repute; as, a house of ill fame, a
      house where lewd persons meet for illicit intercourse.

   {Ill humor}, a disagreeable mood; bad temper.

   {Ill nature}, bad disposition or temperament; sullenness;
      esp., a disposition to cause unhappiness to others.

   {Ill temper}, anger; moroseness; crossness.

   {Ill turn}.
      (a) An unkind act.
      (b) A slight attack of illness. [Colloq. U.S.]

   {Ill will}, unkindness; enmity; malevolence.

   Syn: Bad; evil; wrong; wicked; sick; unwell.

Source : WordNet®

ill at ease
     adj : not at ease socially; unsure and constrained in manner;
           "awkward and reserved at parties"; "ill at ease among
           eddies of people he didn't know"; "was always uneasy
           with strangers" [syn: {awkward}, {ill at ease(p)}, {uneasy}]