When an internet user, regardless of age, posts comments and/or memes poking fun at behaviors and trends which are commonly perceived as unique to millennial (this is in reference to the pseudo-feud between baby-boomers and millennial). These posts, when made by baby-boomers, are typically a way of voicing some level of concern and/or contempt for what they consider "typical millennial" behavior. When posted by other millennials, they are typically a way of that person showing contempt for his/her own generation.
Person A: *posts a picture of a revolver captioned "Fidget spinner... For men"*
Person B: Wow, what a boomerpost!
Person B: Wow, what a boomerpost!
by ( ͡° ͜ʖ ͡*) August 25, 2017
Alt Right jargon referring to the type of language used by baby boomers, especially Republican baby boomers who make unconvincing, poorly formatted posts repeating narratives they heard on Fox News.
Grandmother: "more AFRICAN AMERICANS actually went to PRISON under OBAMA than UNDER BUSH!!!!! OBAMA is BAD FOR THE AFRICAN AMERICANS and they should support TRUMP!!!!!!!!!!!!!"
Grandson 1: "Oh no, what's grandma doing on Facebook now?"
Grandson 2: "Don't worry, she's just boomerposting. She'll get over it."
Grandson 1: "Oh no, what's grandma doing on Facebook now?"
Grandson 2: "Don't worry, she's just boomerposting. She'll get over it."
by FoxyCult April 18, 2017