Mouth off to is an expression that means to talk back to someone in a disrespectful way. The crossword solutions for this term are SASS (4 letters) and SNAPAT (6 letters). SASS stands for 'sarcastic, attitude, sassiness, and style', which is a way of talking back to someone in a rude and disrespectful manner. SNAPAT stands for 'sarcastic, nasty, provocative, aggressive, and taunting', which is another way of talking back to someone in a rude and disrespectful manner.