What is the meaning of Bestemmiare?

to blaspheme

to commit blasphemy [auxiliary avere]

to curse

to curse, to swear, to cuss [auxiliary avere]

to express erroneous judgments, to rant [auxiliary avere]

to offend, to insult

to get angry [auxiliary avere]

to butcher (a language)

to revile

Source: wiktionary.org