Source : Webster's Revised Unabridged Dictionary (1913)

Devil \Dev"il\, n. [AS. de['o]fol, de['o]ful; akin to G. ?eufel,
   Goth. diaba['u]lus; all fr. L. diabolus the devil, Gr. ? the
   devil, the slanderer, fr. ? to slander, calumniate, orig., to
   throw across; ? across + ? to throw, let fall, fall; cf. Skr.
   gal to fall. Cf. {Diabolic}.]
   1. The Evil One; Satan, represented as the tempter and
      spiritual of mankind.

            [Jesus] being forty days tempted of the devil.
                                                  --Luke iv. 2.

            That old serpent, called the Devil, and Satan, which
            deceiveth the whole world.            --Rev. xii. 9.

   2. An evil spirit; a demon.

            A dumb man possessed with a devil.    --Matt. ix.
                                                  32.

   3. A very wicked person; hence, any great evil. ``That devil
      Glendower.'' ``The devil drunkenness.'' --Shak.

            Have not I chosen you twelve, and one of you is a
            devil?                                --John vi. 70.

   4. An expletive of surprise, vexation, or emphasis, or,
      ironically, of negation. [Low]

            The devil a puritan that he is, . . . but a
            timepleaser.                          --Shak.

            The things, we know, are neither rich nor rare, But
            wonder how the devil they got there.  --Pope.

   5. (Cookery) A dish, as a bone with the meat, broiled and
      excessively peppered; a grill with Cayenne pepper.

            Men and women busy in baking, broiling, roasting
            oysters, and preparing devils on the gridiron. --Sir
                                                  W. Scott.

   6. (Manuf.) A machine for tearing or cutting rags, cotton,
      etc.

   {Blue devils}. See under {Blue}.

   {Cartesian devil}. See under {Cartesian}.

   {Devil bird} (Zo["o]l.), one of two or more South African
      drongo shrikes ({Edolius retifer}, and {E. remifer}),
      believed by the natives to be connected with sorcery.

   {Devil may care}, reckless, defiant of authority; -- used
      adjectively. --Longfellow.

   {Devil's apron} (Bot.), the large kelp ({Laminaria
      saccharina}, and {L. longicruris}) of the Atlantic ocean,
      having a blackish, leathery expansion, shaped somewhat
      like an apron.

   {Devil's coachhorse}. (Zo["o]l.)
      (a) The black rove beetle ({Ocypus olens}). [Eng.]
      (b) A large, predacious, hemipterous insect ({Prionotus
          cristatus}); the wheel bug. [U.S.]

   {Devil's darning-needle}. (Zo["o]l.) See under {Darn}, v. t.
      

   {Devil's fingers}, {Devil's hand} (Zo["o]l.), the common
      British starfish ({Asterias rubens}); -- also applied to a
      sponge with stout branches. [Prov. Eng., Irish & Scot.]

   {Devil's riding-horse} (Zo["o]l.), the American mantis
      ({Mantis Carolina}).

   {The Devil's tattoo}, a drumming with the fingers or feet.
      ``Jack played the Devil's tattoo on the door with his boot
      heels.'' --F. Hardman (Blackw. Mag.).

   {Devil worship}, worship of the power of evil; -- still
      practiced by barbarians who believe that the good and evil
      forces of nature are of equal power.

   {Printer's devil}, the youngest apprentice in a printing
      office, who runs on errands, does dirty work (as washing
      the ink rollers and sweeping), etc. ``Without fearing the
      printer's devil or the sheriff's officer.'' --Macaulay.

   {Tasmanian devil} (Zo["o]l.), a very savage carnivorous
      marsupial of Tasmania ({Dasyurus, or Diabolus, ursinus}).
      

   {To play devil with}, to molest extremely; to ruin. [Low]

Blue \Blue\, a. [Compar. {Bluer}; superl. {Bluest}.] [OE. bla,
   blo, blew, blue, Sw. bl?, D. blauw, OHG. bl?o, G. blau; but
   influenced in form by F. bleu, from OHG. bl[=a]o.]
   1. Having the color of the clear sky, or a hue resembling it,
      whether lighter or darker; as, the deep, blue sea; as blue
      as a sapphire; blue violets. ``The blue firmament.''
      --Milton.

   2. Pale, without redness or glare, -- said of a flame; hence,
      of the color of burning brimstone, betokening the presence
      of ghosts or devils; as, the candle burns blue; the air
      was blue with oaths.

   3. Low in spirits; melancholy; as, to feel blue.

   4. Suited to produce low spirits; gloomy in prospect; as,
      thongs looked blue. [Colloq.]

   5. Severe or over strict in morals; gloom; as, blue and sour
      religionists; suiting one who is over strict in morals;
      inculcating an impracticable, severe, or gloomy mortality;
      as, blue laws.

   6. Literary; -- applied to women; -- an abbreviation of
      bluestocking. [Colloq.]

            The ladies were very blue and well informed.
                                                  --Thackeray.

   {Blue asbestus}. See {Crocidolite}.

   {Blue black}, of, or having, a very dark blue color, almost
      black.

   {Blue blood}. See under {Blood}.

   {Blue buck} (Zo["o]l.), a small South African antelope
      ({Cephalophus pygm[ae]us}); also applied to a larger
      species ({[AE]goceras leucoph[ae]u}s); the blaubok.

   {Blue cod} (Zo["o]l.), the buffalo cod.

   {Blue crab} (Zo["o]l.), the common edible crab of the
      Atlantic coast of the United States ({Callinectes
      hastatus}).

   {Blue curls} (Bot.), a common plant ({Trichostema
      dichotomum}), resembling pennyroyal, and hence called also
      {bastard pennyroyal}.

   {Blue devils}, apparitions supposed to be seen by persons
      suffering with {delirium tremens}; hence, very low
      spirits. ``Can Gumbo shut the hall door upon blue devils,
      or lay them all in a red sea of claret?'' --Thackeray.

   {Blue gage}. See under {Gage}, a plum.

   {Blue gum}, an Australian myrtaceous tree ({Eucalyptus
      globulus}), of the loftiest proportions, now cultivated in
      tropical and warm temperate regions for its timber, and as
      a protection against malaria. The essential oil is
      beginning to be used in medicine. The timber is very
      useful. See {Eucalyptus}.

   {Blue jack}, {Blue stone}, blue vitriol; sulphate of copper.
      

   {Blue jacket}, a man-of war's man; a sailor wearing a naval
      uniform.

   {Blue jaundice}. See under {Jaundice}.

   {Blue laws}, a name first used in the eighteenth century to
      describe certain supposititious laws of extreme rigor
      reported to have been enacted in New Haven; hence, any
      puritanical laws. [U. S.]

   {Blue light}, a composition which burns with a brilliant blue
      flame; -- used in pyrotechnics and as a night signal at
      sea, and in military operations.

   {Blue mantle} (Her.), one of the four pursuivants of the
      English college of arms; -- so called from the color of
      his official robes.

   {Blue mass}, a preparation of mercury from which is formed
      the blue pill. --McElrath.

   {Blue mold}, or mould, the blue fungus ({Aspergillus
      glaucus}) which grows on cheese. --Brande & C.

   {Blue Monday}, a Monday following a Sunday of dissipation, or
      itself given to dissipation (as the Monday before Lent).
      

   {Blue ointment} (Med.), mercurial ointment.

   {Blue Peter} (British Marine), a blue flag with a white
      square in the center, used as a signal for sailing, to
      recall boats, etc. It is a corruption of blue repeater,
      one of the British signal flags.

   {Blue pill}. (Med.)
      (a) A pill of prepared mercury, used as an aperient, etc.
      (b) Blue mass.

   {Blue ribbon}.
      (a) The ribbon worn by members of the order of the Garter;
          -- hence, a member of that order.
      (b) Anything the attainment of which is an object of great
          ambition; a distinction; a prize. ``These
          [scholarships] were the --blue ribbon of the
          college.'' --Farrar.
      (c) The distinctive badge of certain temperance or total
          abstinence organizations, as of the --Blue ribbon
          Army.

   {Blue ruin}, utter ruin; also, gin. [Eng. Slang] --Carlyle.

   {Blue spar} (Min.), azure spar; lazulite. See {Lazulite}.

   {Blue thrush} (Zo["o]l.), a European and Asiatic thrush
      ({Petrocossyphus cyaneas}).

   {Blue verditer}. See {Verditer}.

   {Blue vitriol} (Chem.), sulphate of copper, a violet blue
      crystallized salt, used in electric batteries, calico
      printing, etc.

   {Blue water}, the open ocean.

   {To look blue}, to look disheartened or dejected.

   {True blue}, genuine and thorough; not modified, nor mixed;
      not spurious; specifically, of uncompromising
      Presbyterianism, blue being the color adopted by the
      Covenanters.

Source : WordNet®

blue devils
     n : a state of depression; "he had a bad case of the blues"
         [syn: {blues}, {megrims}, {vapors}, {vapours}]