A swear word.
"The driver cursed when he realized his car had stalled on the highway."
promise solemnly; take an oath
"Before climbing the mountain, he swore to return safely within three days."
To take an oath, to promise.
"The tired worker decided to swear on the job by taking a twenty-minute nap at his desk."
To be lazy; rest for a short while during working hours.
In plain English: To swear means to promise something very seriously, often by calling on God as a witness.
"He decided to stop swearing in front of his children."
Usage: Use this word specifically when referring to taking a solemn vow or making a formal promise rather than using it as slang for being lazy. It is often confused with "sworn," which describes the state of having already taken such an oath.
Heavy.
"The heavy snow piled up against the door until it was impossible to open."
The word "swear" comes from the Old English verb swerian, which originally meant to take an oath of office. Its roots trace back through Middle English and Proto-Germanic to a common ancestor meaning simply to speak or swear.