A spat is a short and usually small argument between two people.
When you have a spat with someone, it's not usually serious or long-lasting. You might get annoyed at each other for a little while, but then things calm down. People often use the word "spat" when they want to downplay an argument or make it sound like something silly. For example, if two friends had a disagreement over who left the dishes in the sink, they might say they had a spat about it.
To evacuate (saliva or another substance) from the mouth, etc.
