In 1st Samuel 25, we read about Abigail's first husband, who is named Nabal. Near the end of the story, she pleads with David to save his life:
My lord should not pay attention to this wicked man Nabal. He simply lives up to his name! His name means ‘fool,’ and he is indeed foolish! But I, your servant, did not see the servants my lord sent.—1st Samuel 25:25 (NET)
So there seem to be three possibilities:
Nabal's parents thought it would be a good idea to name their son Fool. (This is perhaps not as unlikely as it seems.)
Nabal didn't mean fool when it was given as a name. (Perhaps the meaning arose from this story or perhaps it came from another language or dialect.)
His name was unrecorded initially and supplied by a later editor.
How should we read this unusual name?