At first glance this word looks like the name of an insane asylum (Bedlam). I was surprised to see Shakespeare mentioning this… until a closer look at the spelling. Whoopsie!
beldam (n.) IPA Pronunciation: 
old woman, hag
HUBERT
Old men and beldams in the streets
Do prophesy upon it dangerously:
– KING JOHN (IV.ii)
In some instances the word does not have such a positive connotation. You would not address an old woman as Beldam if you wanted to be respectful. So if you offend your grandmother this way, don’t blame me. Blame her for knowing what the word actually means! Then wash your mouth out with soap.