\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["a]rja, Dan. sv[ae]rge,
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.
         Ye shall swear by my name falsely.    --Lev. xix.
                                               12.
         I swear by all the Roman gods.        --Shak.
2. (Law) To give evidence on oath; as, to swear to the truth
   of a statement; he swore against the prisoner.
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.
         [I] swore little; diced not above seven times a
         week.                                 --Shak.
{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]

\Swear\, v. t.
1. To utter or affirm with a solemn appeal to God for the
   truth of the declaration; to make (a promise, threat, or
   resolve) under oath.
         Swear unto me here by God, that thou wilt not deal
         falsely with me.                      --Gen. xxi.
                                               23.
         He swore consent to your succession.  --Shak.
2. (Law) To put to an oath; to cause to take an oath; to
   administer an oath to; -- ofetn followed by in or into;
   as, to swear witnesses; to swear a jury; to swear in an
   officer; he was sworn into office.
3. To declare or charge upon oath; as, he swore treason
   against his friend. --Johnson.
4. To appeal to by an oath.
         Now, by Apollo, king, Thou swear'st thy gods in
         vain.                                 --Shak.
{To swear the peace against one}, to make oath that one is
   under the actual fear of death or bodily harm from the
   person, in which case the person must find sureties that
   he will keep the peace.