Blather, bladdher; a person who utters vulgarly foolish boastful talk: used also as a verb—to blather.

What is a blathering?

(Entry 1 of 2) : foolish or nonsensical talk or writing … liked to conduct five meetings at once, moving back and forth between them, looking for the moment when the blathering was done and the dealing had begun.— Karen Breslau …

Is it blathering or blithering?

As nouns the difference between blathering and blithering

is that blathering is incoherent or foolish talk while blithering is incoherent or foolish talk.