a slang word used to stop someone from saying something negative about another person that isn't around to defend themselves.
Josh said "Wow, did you see her outfit, she looks like she just came from the dollar store and they didn't even have her size" Grant said you need to "Squash it and be nice!!"
A person you hate intensely not because they deserve such hatred but because they serve as a focus for your general hatred. A healthy way to dispense with excess animosity.
Jake's not really that big an asshole. He just serves as my hate sink.