Someone who takes a solemn oath

Usage examples of swearer.

One-eyed Bogan, who had been the worst swearer in a rough shed, and he fell back on his bunk as if his previous remarks had exhausted him.

Avarice, or Covetousness, which is the root of all harms, since its votaries are idolaters, oppressors and enslavers of men, deceivers of their equals in business, simoniacs, gamblers, liars, thieves, false swearers, blasphemers, murderers, and sacrilegious.

These were commanded by the Suy Dams, and the Van Dams,--incontinent hard swearers, as their names betoken.

I see but murderers, adulterers, conspirators, false swearers, men in perpetual terrors, and betrayed by their dearest friends and acquaintance.

Art og mac Morna of the Hard Strokes fell to biting his fingers, Cona'n the Swearer and Garra mac Morna grumbled irritably to each other and at their neighbours, even Caelte, the son of Rona'n, looked down into his own lap, and Goll Mor sipped at his wine without any twinkle in his eye.