Past Tense of “swear”
The past tense of swear is swore; the past participle is sworn.
Why “swear” behaves this way
"Swear" comes from Old English "swerian," a Class VI strong verb in the same ablaut family as "bear/bore/borne" and "tear/tore/torn" — present, simple past, and participle marching through the same long-e, long-o, long-o-plus-en vowel sequence those two verbs also follow. Its original and still-central sense was to make a solemn declaration or vow, often before witnesses or a deity — the same root behind "answer" (originally "and-swerian," to swear back or respond) and behind the specifically legal sense of swearing an oath in court, which remains one of the verb's most formal and important modern uses.
The verb's second major modern sense, using profane or vulgar language, developed later as a specialized narrowing from the oath-taking sense — the connection being that early curses and profanities were often literally blasphemous oaths invoking a deity's name inappropriately, so "swearing" in the profane sense grew directly out of "swearing" in the solemn, religious sense, even though the two meanings feel almost opposite in tone today. This dual meaning has stayed stable in English for centuries, and both senses have coexisted comfortably since at least Middle English, with context alone reliably telling readers whether a courtroom oath or an angry outburst is intended.
The common confusion
The main confusion for learners is the vowel-shape shift between "swore" and "sworn," easily mixed up in the perfect tense ("I have swore" instead of the correct "I have sworn"), a mistake common enough in casual speech that it ranks among frequently corrected errors, similar to the "spoke"/"spoken" mix-up. A separate confusion involves keeping the profanity sense and the oath sense straight in context, since "she swore at the referee" and "she swore to tell the truth" use the identical verb form to describe very different kinds of speech. A third, more legal point of confusion is distinguishing a formally "sworn" affidavit from an ordinary written statement, a distinction with real legal consequences that hinges entirely on whether the specific oath-taking procedure was actually performed.
How it's actually used
"Sworn" also functions as a standalone adjective in fixed legal and formal phrases — "a sworn statement," "a sworn enemy," "sworn testimony" — where it describes something formally affirmed or firmly committed to, a productive adjectival use built directly on the oath-taking sense rather than the profanity sense. The phrasal verb "swear off" (renouncing something, as in "he swore off gambling") is a distinctly modern extension that treats quitting a habit like a formal, almost ceremonial vow, borrowing the gravity of the oath-taking sense for an everyday personal resolution.
Across the tense system
The passive voice appears constantly in legal writing — "the witness was sworn in before testifying," "the officers have been sworn to secrecy" — where the ceremonial, formal nature of oath-taking naturally lends itself to passive constructions describing what was done to a person in an official proceeding. The profanity sense, by contrast, almost always stays in the active voice, since swearing at someone is inherently framed as a deliberate act performed by a clearly identified speaker rather than something that simply happens to a passive recipient.
Common real mistakes
The dominant error is "I have swore" instead of the correct "I have sworn" — the identical simple-past-for-participle swap that dogs "spoke"/"spoken." A second, much rarer error is confusing "sworn" with the unrelated "shorn" (past participle of "shear") in fast speech, two words that share a rhyme but come from entirely different verbs with unrelated meanings. A third error, seen in casual writing, is using the profanity sense with an incorrect regularized form, "she sweared at him," when the same irregular conjugation applies to both the oath-taking sense and the profanity sense without exception. A fourth, more legal error is confusing a "sworn affidavit" with an ordinary signed letter, a distinction that matters considerably in court, since only the former carries the legal weight of an oath.
Examples
- She swore to tell the truth before the judge.
- He has sworn off sweets for the rest of the year.
- The witness was sworn in before giving testimony.
- They swore they would never speak to each other again.
- He swore under his breath when he missed the shot.
- The new officers have sworn an oath to serve the community.
Memory trick
Line "swear" up next to "tear/tore/torn" and "bear/bore/borne" — a different strong-verb class, but one that happens to walk through the same three vowel stages. Drop "torn" into a sentence where you're unsure about "swore" versus "sworn" and see if it still reads naturally, whether the context is a courtroom oath or an angry outburst.