Warning: Not for the politically-correct faint-of-heart.
This definition is care of Psychology Today:
Groupthink is a phenomenon that occurs when a group of well-intentioned people make irrational or non-optimal decisions spurred by the urge to conform or the belief that dissent is impossible. The problematic or premature consensus that is characteristic of groupthink may be fueled by a particular agenda—or it may be due to group members valuing harmony and coherence above critical thought.
I read a Facebook post today opining how “up” has become “down” and “down” has become “up”. The tail now wags the dog in many ways throughout our society. The Facebook poster talked about what I call the groupthink of enforced political correctness. Yet these “conventions” of political correctness are now strangely accepted as normal and sane.