What does swear mean?
Swear has two widely used meanings. In its traditional sense, it means to make a solemn promise, often by invoking God or another sacred authority as a witness: people swear an oath, swear allegiance, or swear that something is true. This use suggests commitment, seriousness, and sometimes the formal authority of a declaration. More informally, to swear means to use profane or offensive language, especially when angry, frightened, frustrated, or surprised. The distinction is important because the same word can move from a legal or ceremonial promise to an everyday expression of irritation. Swear also means to express a firm declaration, as in “I swear I am telling the truth,” where it reinforces the sincerity of the statement. Its historical association with oaths explains why the word continues to carry a sense of solemnity, while its modern use as an intensifier reflects the broader flexibility of English vocabulary.
To make a solemn promise or oath, or to express a firm commitment or declaration.
"The witnesses swore that they had seen nothing."
The promise sense is formal and solemn, especially when used with an oath, an authority, or an appeal to something sacred.
To use offensive or impolite language, especially in anger, frustration, or surprise.
"He swore when the computer crashed for the third time."
This is an informal use and is often an intensifier rather than a serious attempt to offend.
An oath or solemn promise.
"The official made a swear of impartiality."
The noun sense is much less common than the verb senses and is chiefly formal or archaic.
Swear began as a solemn act of promising, but the same word now also delivers some of English's most memorable outbursts.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does swear come from?
The word descends from Old English swerian, meaning “to make an oath” or “to promise solemnly.” Its exact ultimate origin is debated, although the Old English verb belongs to a Germanic family of forms connected with swearing or swearing an oath. Modern English developed the regular past tense swore and past participle sworn, forms that also reflect older Germanic patterns.
Related word forms
How swear is actually used
In its promise sense, the word is formal and carries the implication of seriousness or solemn responsibility; it is stronger and more emphatic than an ordinary promise. In the offensive-language sense, it is common in informal speech and may also occur in literary or dramatic contexts for emphasis.
Easily confused with swear
To swear is to promise solemnly or use offensive language, whereas to sweat is to perspire, especially from heat, exertion, or anxiety.