The Collaborative International Dictionary of English v.0.48:

Breast \Breast\ (br[e^]st), n. [OE. brest, breost, As.
   bre['o]st; akin to Icel. brj[=o]st, Sw. br["o]st, Dan. bryst,
   Goth. brusts, OS. briost, D. borst, G. brust.]
   1. The fore part of the body, between the neck and the belly;
      the chest; as, the breast of a man or of a horse.
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   2. Either one of the protuberant glands, situated on the
      front of the chest or thorax in the female of man and of
      some other mammalia, in which milk is secreted for the
      nourishment of the young; a mamma; a teat.
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            My brother, that sucked the breasts of my mother.
                                                  --Cant. viii.
                                                  1.
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   3. Anything resembling the human breast, or bosom; the front
      or forward part of anything; as, a chimney breast; a plow
      breast; the breast of a hill.
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            Mountains on whose barren breast
            The laboring clouds do often rest.    --Milton.
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   4. (Mining)
      (a) The face of a coal working.
      (b) The front of a furnace.
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   5. The seat of consciousness; the repository of thought and
      self-consciousness, or of secrets; the seat of the
      affections and passions; the heart.
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            He has a loyal breast.                --Shak.
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   6. The power of singing; a musical voice; -- so called,
      probably, from the connection of the voice with the lungs,
      which lie within the breast. [Obs.]
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            By my troth, the fool has an excellent breast.
                                                  --Shak.
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   Breast drill, a portable drilling machine, provided with a
      breastplate, for forcing the drill against the work.

   Breast pang. See Angina pectoris, under Angina.

   To make a clean breast, to disclose the secrets which weigh
      upon one; to make full confession.
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The Collaborative International Dictionary of English v.0.48:

Clean \Clean\ (kl[=e]n), a. [Compar. Cleaner (kl[=e]n"[~e]r);
   superl. Cleanest.] [OE. clene, AS. cl[=ae]ne; akin to OHG.
   chleini pure, neat, graceful, small, G. klein small, and
   perh. to W. glan clean, pure, bright; all perh. from a
   primitive, meaning bright, shining. Cf. Glair.]
   1. Free from dirt or filth; as, clean clothes.
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   2. Free from that which is useless or injurious; without
      defects; as, clean land; clean timber.
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   3. Free from awkwardness; not bungling; adroit; dexterous;
      as, a clean trick; a clean leap over a fence.
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   4. Free from errors and vulgarisms; as, a clean style.
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   5. Free from restraint or neglect; complete; entire.
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            When ye reap the harvest of your land, thou shalt
            not make clean riddance of corners of thy field.
                                                  --Lev. xxiii.
                                                  22.
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   6. Free from moral defilement; sinless; pure.
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            Create in me a clean heart, O God.    --Ps. li. 10
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            That I am whole, and clean, and meet for Heaven
                                                  --Tennyson.
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   7. (Script.) Free from ceremonial defilement.
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   8. Free from that which is corrupting to the morals; pure in
      tone; healthy. "Lothair is clean." --F. Harrison.
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   9. Well-proportioned; shapely; as, clean limbs.
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   A clean bill of health, a certificate from the proper
      authority that a ship is free from infection.

   Clean breach. See under Breach, n., 4.

   To make a clean breast. See under Breast.
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