Noun
professional suicide (countable and uncountable, plural professional suicides)
(idiomatic) An action by a person that is expected to ruin their own career.
2019 October 4, Davidson, Joe, “Perspective | Federal whistleblowers would do it again, even after retaliation and ‘professional suicide’”, in Washington Post:“As a rule, whistleblowing is an act of professional suicide,” said Tom Devine, legal director of the Government Accountability Project that defends whistleblowers. The threat of retaliation “exponentially increases when Trump calls you a spy.”