IPA: /ˈpɜːrdʒər/
KK: /ˈpɜr.dʒər/
A person who lies or makes false statements while under oath, especially in a court of law.
The witness was found to be a perjurer after it was revealed that he lied during the trial.
Perjurer → It is formed from "per-" (meaning through) and "jurare" (meaning to swear). A perjurer is someone who swears falsely or lies under oath, thus going through the act of swearing dishonestly.
Think of someone who swears ('jurare') falsely ('per-'), which helps you remember that a perjurer is someone who lies while under oath.