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]