The most heartless, demoralizing, or treacherous action, remark, or outcome possible. A reference to a line in Shakespeare's Julius Caesar, describing Caesar's death at the hands of his friends. But the unkindest cut was watching the man I considered my best friend move in with my ex-wife the second I moved out. Even my teachers stood there laughing at me. That was the most unkindest cut of all. Seeing such a beloved character turned into such an absurd parody of herself, well, that's the unkindest cut of all for longtime fans of the series.

The most hurtful or malicious thing that one could say to another. The phrase originated in Shakespeare's Julius Caesar in a description of Caesar's murder. Hearing my own mother attack my decision to adopt a child was the most unkindest cut of all.