to make a solemn statement, promise, or declaration by some sacred being or object, as a deity or the Bible: [no object][usually: not: be + ~-ing]He swore on the Bible.[~ + (that) clause]He swore (that) he would tell the truth.[~ + to + verb]You swore to tell the truth.
to use obscene or profane language: [no object]He swore viciously when the driver cut him off.[~ + at + object]He swore at the driver who cut him off.[used with quotations]"That's all I damn well need!'' he swore.
to bind or make (someone) promise by an oath:[~ + object + to + object]They swore her to secrecy.
swear by, [usually: not: be + ~-ing* ~ + by + object]
to name (a sacred being or object) as one's witness:I swear by my mother's grave that what I'm telling you is true.
to have great confidence in; trust in:Whenever he has a cold he swears by this mixture of tea, lemon juice, and honey.
swear in, to admit to office or service by administering an oath: [~ + in + object]The Chief Justice swore in the President.[~ + object + in]to swear him in.
swear off, [~ + off + object] to promise (oneself) to give up (something):He said he had sworn off drugs and alcohol.
Lawswear out, [~ + out + object] to secure (a warrant for arrest) by making an accusation under oath:to swear out a warrant for his arrest.