A put-down used to tell an ignorant or closed-minded person of the baby-boomer generation that you do not respect their opinion because it's built on misinformation or ignorance so great that it's unreasonable to try and undo it all in the current conversation. Typically, one who uses this phrase does so because they realise that the person they're talking to would not be willing or able to enter a reasonable discussion about their misinformed opinion.
Boomer: "You millennials are so lazy, you think you're entitled to an easy life. You don't know how the world really works. By the time I was your age I'd paid off my mortgage because I worked hard."
Millennial: "OK boomer"
Millennial: "OK boomer"
by Pablo Guardo February 26, 2020
Get the OK Boomermug. Someone born during the "baby boom" following WWII. Boomers were coddled by their parents and led to believe that they could achieve anything they dreamed of and that they were perfect just as they are. They deeply resent the society they created based on this terrible advice, and the progeny they misguidedly trained to perpetuate it. As a result, reality bites boomers in ways more acutely painful than subsequent generations can possibly understand.
Boomer (60-75-year-old): You're chasing your dreams instead of mine. This can't be right.
Millennial/zoomer: ok boomer.
Boomer: My parents acted as though I were the center of the universe and I insist that you do the same.
Millennial/zoomer: I have spoken.
Millennial/zoomer: ok boomer.
Boomer: My parents acted as though I were the center of the universe and I insist that you do the same.
Millennial/zoomer: I have spoken.
by ArguingKitten December 14, 2019
Get the Boomermug. 
If you searched the definition of this, you are a boomer
by I am a mop August 22, 2020
Get the boomermug. 
by DUMBHOE!@#$%^ December 13, 2019
Get the Boomermug. by Ash masters April 22, 2020
Get the the boomer consumermug.