When a teen condescendingly assumes that they know more about a topic than the adults around them, usually their parents. The teen then explains the topic to the adult as if the adult is completely ignorant regardless of their experience or expertise. This is frequently accompanied by the extreme certainty that can only be maintained through inexperience.
Maya was teensplaining to me that intelligence is about 75% heritable.
"You'd know that if you weren't such an idiot, Dad!"

My daughter teensplained pop music to me, as if I hadn't lived through the 80s.
by ZippySanjay June 21, 2017
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Similar to mansplaining but with a teenager who firmly believes he/she/they know everything, and are therefore obligated to explain it to you. Often accompanied with an eye roll followed by stomping and a door slam.
(Mom and Teenager watching Home Alone)
Teen: Mom, wait until you see what happens when the power goes out.

Mom: You mean when their phone lines are down?
Teen: Did know that phones went down back then?
Mom: Yes.
Teen: Well, it was because there weren't cell phones and they had phone calls go through wires.

Mom: I know. I was a kid at the time.

Teen: But this is different, Mom. You just don't understand! (Eye roll / stomp away)
Mom: I cannot believe he just teensplaining me about something I experienced 30 years before he existed! How does he think she automatically knows more than me and has to explain it?
by Bananago December 7, 2020
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a teen who thinks they know more about a topic then their parent and then explains it to them
Alice is such a teensplainer, the other day she was explaining 80's culture.
Like i haven't lived through the 80's myself
by Raccooty March 5, 2018
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