1. superlative form of foul; most disgusting, offensive, or unpleasant in smell, taste, or appearance
2. superlative form of foul; most morally corrupt, evil, or wicked
3. superlative form of foul; most unfair or dishonest

Examples

• The basement had the foulest smell after the flood.
• That was the foulest weather we’ve had all winter.
• He committed the foulest crime in the city’s history.
• The villain’s foulest deed was betraying his own family.
• The referee called the foulest play of the entire game.
• She used the foulest language when she was angry.