The Collaborative International Dictionary of English v.0.48:

Swear \Swear\, v. i. [imp. Swore, formerly Sware; p. p.
   Sworn; p. pr. & vb. n. Swearing.] [OE. swerien, AS.
   swerian; akin to D. zweren, OS. swerian, OHG. swerien, G.
   schw["o]ren, Icel. sverja, Sw. sv[aum]rja, Dan. svaerge,
   Icel. & Sw. svara to answer, Dan. svare, Dan. & Sw. svar an
   answer, Goth. swaran to swear, and perhaps to E. swarm.
   [root]177. Cf. Answer.]
   1. To affirm or utter a solemn declaration, with an appeal to
      God for the truth of what is affirmed; to make a promise,
      threat, or resolve on oath; also, to affirm solemnly by
      some sacred object, or one regarded as sacred, as the
      Bible, the Koran, etc.
      [1913 Webster]

            Ye shall swear by my name falsely.    --Lev. xix.
                                                  12.
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            I swear by all the Roman gods.        --Shak.
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   2. (Law) To give evidence on oath; as, to swear to the truth
      of a statement; he swore against the prisoner.
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   3. To make an appeal to God in an irreverant manner; to use
      the name of God or sacred things profanely; to call upon
      God in imprecation; to curse.
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            [I] swore little; diced not above seven times a
            week.                                 --Shak.
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   To swear by, to place great confidence in a person or
      thing; to trust implicitly as an authority. "I simply
      meant to ask if you are one of those who swear by Lord
      Verulam." --Miss Edgeworth.

   To swear off, to make a solemn vow, or a serious
      resolution, to abstain from something; as, to swear off
      smoking. [Slang]
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The Collaborative International Dictionary of English v.0.48:

Swearing \Swear"ing\,
   a. & n. from Swear, v.
   [1913 Webster]

         Idle swearing is a cursedness.           --Chaucer.
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WordNet (r) 3.0 (2006):

swearing
    n 1: profane or obscene expression usually of surprise or anger;
         "expletives were deleted" [syn: curse, curse word,
         expletive, oath, swearing, swearword, cuss]
    2: a commitment to tell the truth (especially in a court of
       law); to lie under oath is to become subject to prosecution
       for perjury [syn: oath, swearing]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "swearing":
   affidavit, affirmation, attestation, bad language, billingsgate,
   blue language, certification, colorful language, cursing, cussing,
   deposition, dirty language, dirty talk, dysphemism, evil speaking,
   execration, filth, filthy language, foul language, imprecation,
   notarized statement, obscenity, profane swearing, profanity,
   ribaldry, scatology, statement under oath, strong language,
   sworn statement, sworn testimony, testimony,
   unparliamentary language, unrepeatable expressions, vile language,
   vouching, vulgar language