blasphémer

to blaspheme

“Cessez de blasphémer, vile créature ! Apprenez, ignorante, que saint Prétextat était archevêque de Rouen au VIᵉ siècle, et grand ami de Grégoire de Tours, qui était un homme très bien, dont vous n’avez naturellement jamais entendu parler.” — Stop blaspheming, you vile creature! You’d better learn, ignorant woman, that Saint Praetextatus was Archbishop of Rouen in the 6ᵗʰ century, and a friend of Gregory of Tours, who was a very good man, which you, unsurprisingly, never heard of.

From Old French blasfemer, which was borrowed from Late Latin blasphēmāre. Doublet of blâmer, which was inherited.