The Collaborative International Dictionary of English v.0.48:

Ill \Ill\ ([i^]l), 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.
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            Neither is it ill air only that maketh an ill seat,
            but ill ways, ill markets, and ill neighbors.
                                                  --Bacon.
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            There 's some ill planet reigns.      --Shak.
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   2. Contrary to good, in a moral sense; evil; wicked; wrong;
      iniquitious; naughtly; bad; improper.
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            Of his own body he was ill, and gave
            The clergy ill example.               --Shak.
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   3. Sick; indisposed; unwell; diseased; disordered; as, ill of
      a fever.
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            I am in health, I breathe, and see thee ill. --Shak.
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   4. Not according with rule, fitness, or propriety; incorrect;
      rude; unpolished; inelegant.
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            That 's an ill phrase.                --Shak.
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   Ill at ease, uneasy; uncomfortable; anxious. "I am very ill
      at ease." --Shak.

   Ill blood, enmity; resentment; bad blood.

   Ill breeding, lack 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.
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The Collaborative International Dictionary of English v.0.48:

Ease \Ease\ ([=e]z), 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.]
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            They him besought
            Of harbor and or ease as for hire penny. --Chaucer.
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   2. Freedom from anything that pains or troubles; as:
      (a) Relief from labor or effort; rest; quiet; relaxation;
          as, ease of body.
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                Usefulness comes by labor, wit by ease.
                                                  --Herbert.
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                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.
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                Among these nations shalt thou find no ease.
                                                  --Deut.
                                                  xxviii. 65.
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                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.
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                True ease in writing comes from art, not chance.
                                                  --Pope.
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                Whate'er he did was done with so much ease,
                In him alone 't was natural to please. --Dryden.
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   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; tranquillity;
        facility; easiness; readiness.
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WordNet (r) 3.0 (2006):

ill at ease
    adj 1: socially uncomfortable; 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]