I would set a one-on-one meeting with my colleague to address why he/she keeps undermining my decisions, as repeated incidents can disrupt teamwork. If his/her actions stem from personal dislike or a habit of opposition, it could act like a parasite slowing down or even reversing a car that is moving forward. However, I acknowledge that criticism and suggestions are important. Instead of merely opposing, I will encourage him/her to focus on providing solutions and constructive problem-solving, fostering a more collaborative approach. And if he/she refuses a one-on-one meeting, I will assume that he/she does not want to resolve the issue with me. Maybe I will request a division transfer or ask my boss to transfer me to another division.

A colleague keeps undermining your decisions in team meetings. To handle this professionally, I would document, document, document. Before the meeting, email the team a brief summary of your decision or idea. I have tried this in the past, and it minimizes what said colleague is able to undermine during the meeting.