- noun (countable usually singular)
AmE a condition in which your back curves inward too much
swear, verb past tense swore, past participle sworn
1 OFFENSIVE LANGUAGE (I) to use offensive language, especially because you are angry: Don't swear in front of the children.(+ at): Rich tripped over the dog and swore at it. | swear like a trooper (=use very offensive language)2 SERIOUS PROMISE (T) to make a very serious promise: swear to do sth: Mona swore never to return home. | swear (that): Victor swore he would get his revenge.(+ on/by): Do you swear on your honour never to tell anyone?3 PUBLIC PROMISE (I, T) to make a public official promise, especially in a court of law(+ on): Witnesses have to swear on the Bible. | swear an oath: Before giving evidence you have to swear an oath to tell the truth. | swear allegiance: Presidents must swear allegiance to the US constitution.4 STATE THE TRUTH (transitive not in progressive) informal to say that what you have said is the truth: swear (that): He says he was there all the time, but I swear I never saw him. | swear blind (that) informal (=used to emphasize you are telling the truth): She swore blind that she had never met the man. | I could have sworn (that) informal (=I was almost certain): I could have sworn I left the keys on that table. | swear to God: I never touched her I swear to God.5 swear sb to secrecy/silence to make someone promise not to tell anyone what you have told themswear by sth phrasal verb (transitive not in progressive) informal to have great confidence in the effectiveness of something: He swears by vitamin C pills, and says he never gets ill. swear sb in phrasal verb (transitive usually passive)1 to make someone promise publicly to be loyal to a country, official job etc: The new governor was sworn in. | the swearing-in ceremony2 to make someone give an official promise in a court of law: The jury had to be sworn in first.swear off sth phrasal verb (T) to promise to stop doing something that is bad for you: I'm swearing off alcohol after last night! swear to phrasal verb (T) not swear to (doing) sth to be unwilling to say that something is true because you are not sure about it: I think it was Sue I saw, but I wouldn't swear to it.
Longman dictionary of contemporary English. 2004.