make a solemn statement or promise undertaking to do something or affirming that something is the case

Maria made me swear I would never tell anyone

‘Never again,’ she swore, ‘will I be short of money’

they were reluctant to swear allegiance

use language of a kind regarded as coarse, blasphemous, or otherwise unacceptable in polite or formal speech in order to express anger or other strong emotion

Peter swore under his breath

he was sent off for swearing at the referee