Definition: Foul-mouthedness is a term used to describe someone who has an unpleasant or offensive tone in their speech, especially when speaking about someone else's opinions or beliefs. This can be characterized by words that are harsh and unkind towards them, often accompanied by negative comments or sarcasm. It is not uncommon for people with foul-mouthedness to become defensive or angry towards others, which can lead to conflicts or misunderstandings in social situations.